United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R04-93/146
June 1993
SEPA Superfund
Record of Decision:
Peak Oil/Bay Drum
(Operable Unit 1), FL
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50272-101
REPORT DOCUMENTATION
PAGE
1. REPORT NO.
EPA/ROD/R04-93/146
3. R»cipiont'§ Accession No.
Title and Subtitle
SUPERFUND RECORD OF DECISION
Peak Oil/Bay Drum (Operable Unit 1), FL
Second Remedial Action
5. Report Date
06/21/93
6.
7. Authors)
8. Performing Organization Rept. No.
9. Performing Organization Name and Address
10 Project Task/Work Unit No.
11. Contract(C)orGrant(G)No.
(C)
(G)
12. Sponsoring Organization Name and Address
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
13. Type of Report A Period Covered
800/800
14.
15. Supplementary Notes
PB94-964031
16. Abstract (Limit: 200 words)
The 4-acre Peak Oil/Bay Drum (Operable Unit 1) site is a former used oil refinery in
Brandon, Hillsborough County, Florida. Land use in the area is predominantly
industrial and undeveloped, with three wetlands areas located adjacent to the site.
The nearest residential area is located 0.3 miles east of the site. Although not
utilized currently, onsite ground water is classified as a class II aquifer; and
therefore, is a viable source of ground water for future consumption. From 1954 to
1979, the Peak Oil facility re-refined used oil with an acid clay purification and
filtration process to purify used oils and lubrication fluids. Used oils accepted at
the facility for re-refining consisted primarily of used auto and truck crankcase oil,
with some hydraulic oil, transformer fluid, and other used oils. The acid clay
filtration process generated a low-pH sludge and oil saturated clay, which was stored
over the life of the site in three separate impoundment areas, known as lagoons 1, 2,
and 3. These unlined impoundments measured approximately 90 by 100 feet, and lagoons 1
and 3 were connected by an oil/water separator. In late 1979 or 1980, the company
discontinued the re-refining process and began to filter and blend used oil for resale.
At this time, company employees reported leaks and spills from onsite storage tanks,
trucks, and oil/water separators; and that the wastes from the refining operations
(See Attached Page)
17. Document Analysis a. Descriptors
Record of Decision - Peak Oil/Bay Drum (Operable Unit 1), FL
Second Remedial Action
Contaminated Media: soil, sediment, debris
Key Contaminants: organics (PAHs, PCBs), metals (lead)
b. Identifiers/Open-Ended Terms
c. COSAT1 Field/Group
18. Availability Statement
19. Security Class (This Report)
None
20. Security Class (This Page)
None .
21. No. of Pages
94
22. Price
(Se0ANSI-Z39.18)
£•« Instructions on Reverse
OPTIONAL FORM 272 (4-77)
[Formerly NTIS-35)
Department of Commerce
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EPA/ROD/R04-93/146
Peak Oil/Bay Drum (Operable Unit 1), FL
Second Remedial Action
Abstract (Continued)
continued to be stored in the onsite lagoons. Lagoons 1 and 3 subsequently were
backfilled, but a visible oily residue exists over the entire thickness of these former
lagoons. EPA conducted inspections at the Peak Oil and Bay Drum sites and reported that
various chemical constituents were present in site soil, including heavy metals, petroleum
hydrocarbons, PCBs, and solvent-type chemical compounds. In 1986, EPA initiated a removal
action utilizing a mobile incinerator to treat approximately 4,000 yd^ of acidic PCB
sludge found in lagoon 2. Approximately 6,000 yd^ of resultant ash generated during the
incineration process was placed on and covered with a protective plastic cover at the
site. A previous 1993 ROD addressed soil and sediment remediation at the Bay Drums area,
as OU3. This ROD addresses contaminated soil, sediment, and debris (ash pile) at the Peak
Oil site, as OU1. Future RODs will address contaminated ground water at the Peak Oil and
Bay Drums sites, and wetlands at the entire site, as OUs 2 and 4, respectively. The
primary contaminants of concern affecting the soil, sediment, and debris are organics,
including PAHs and PCBs; and metals, including lead.
The selected remedial action for this site includes demolishing onsite structures;
constructing a clay slurry wall around the impacted site at an average depth of 20 feet to
enclose an area of approximately 6 acres of contaminated soil; installing extraction wells
to dewater the surficial soil within the slurry wall; excavating lead-impacted soil with
concentrations above the remediation goal of 284 mg/kg and onsite debris with lead levels
greater than 284 mg/kg, followed by onsite solidification/stabilization and disposal of
these materials; conducting treatability studies to determine whether treatment of the
organic-contaminated soil should be performed before or after solidification, since
organic contamination may hinder the ability to meet solidification performance standards;
flushing the soil using in-situ bioremediation of organic-contaminated soil using
nutrient-enriched ground water (from the concurrent ground water ROD OU2); providing for a
contingency remedy for treatment by vacuum extraction/soil aeration, to be added during
the remedial design, if it is determined that this process is more effective in removing
VOCs; installing a multi-media cap with perimeter drains to cover the entire area enclosed
by the slurry wall; monitoring ground water; and implementing institutional controls,
including deed restrictions. The estimated present worth cost for this remedial action is
$3,947,165, which includes an estimated total O&M cost of $428,000 for 30 years.
PERFORMANCE STANDARDS OR GOALS:
Chemical-specific soil, sediment, and debris cleanup goals are based upon protection of
ground water and were calculated using SDWA MCLs and EPA-recommended remediation goals for
PCBs in soil and industrial areas, and include Arochlor 1260 25 mg/kg;
bis(2-ethylhexyl)phthalate 0.58 mg/kg; and lead 284 mg/kg.
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RECORD OF DECISION
OPERABLE UNIT 1
PEAK OIL SOURCE CONTROL
PEAK OIL/BAY DRUMS SITE
Brandon, Hillsborough County, Florida
IK
O
Prepared By:
Environmental Protection Agency
Region IV
Atlanta, Georgia
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RECORD OF DECISION
PEAK OIL SOURCE CONTROL
OPERABLE UNIT ONE
PEAK OIL/BAY DRUMS NPL SITE
DECLARATION
SITE NAME AND LOCATION
Peak Oil/Bay Drums Superfund Site
Brandon, Hillsborough County, Florida
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial action for
Operable Unit One at the Peak Oil/Bay Drums Site in Brandon,
Hillsborough County, Florida, which was .chosen in accordance with
the Comprehensive Environmental Response Compensation and
Liability Act of 1980 (CERCLA), as amended by the Superfund
Amendments Reauthorization Act of 1986 (SARA), and, to the extent
practicable, the National Oil and Hazardous Substances Pollution
Contingency Plan (NCP). This decision is based on the
administrative record file for this site.
The State of Florida, as represented by the Florida Department of
Environmental Regulation (FDER), has been the support agency
during the Remedial Investigation and Feasibility Study process
for the Peak Oil/Bay Drums site. In accordance with 40 CFR
300.430, as the support agency, FDER has provided input during
the process. Based upon comments received from FDER, it is
expected that concurrence will be forthcoming; however, a formal
letter of concurrence has not yet been received.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this
site, if not addressed by implementing the response action
selected in this Record of Decision (ROD), may present an
imminent and substantial endangerment to public health, welfare,
or the environment.
DESCRIPTION OF THE REMEDY
The remedy selected by EPA for the Peak Oil/Bay Drums Site will
be conducted in four separate operable units. Operable'Unit One,
which is addressed in this Record of Decision, will address the
source of contamination which represents a principal threat at
the Peak Oil Site through an in-situ treatment alternative which
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includes process technologies that will treat impacted soils,
sediments and the ash pile. Operable Unit Two will address the
appropriate remediation for the groundwater at the Peak Oil and
Bay Drums Sites. Operable Unit Three will address the source of
contamination at the Bay Drums Site. Operable Unit Four will
address the appropriate remediation for the surrounding wetlands
at the Peak Oil, Bay Drums and Reeves Southeastern Sites.
Operable Units Two, Three and Four will be addressed in separate
Records of Decision.
The major components of the selected remedy for Operable Unit One
include:
o demolition of buildings, fence, and railroad tracks, where
necessary, to construct the slurry wall;
o construction of a slurry wall around the impacted site
soils;
o construction of a chain-link fence and placement of warning
signs around the perimeter of the s.ite;
o installation of a groundwater recovery system which includes
extraction wells and collection header piping;
o installation of a mixing system to add necessary nutrients
and dissolved oxygen (or hydrogen peroxide) to the
groundwater for infiltration;
o installation of a delivery system (leach field piping or
spray irrigation) to provide infiltration of treated
groundwat er;
o implement weekly maintenance and operation of in-situ
treatment system;
o implement periodic monitoring to optimize the hydrodynamics
of the extraction wells and infiltration field, track the
effectiveness of the biodegradation and soil flushing
processes, and maintain the levels of nutrients and oxygen
in the media at proper levels to ensure biodegradation;
o solidification/stabilization of lead-impacted soil with
concentrations above the remediation goal of 284 milligrams
per kilogram (mg/kg);
o solidification/stabilization of the ash pile;
o on-site disposal of solidified/stabilized soil and* ash;
o installation of a multimedia cap after in-situ treatment is
completed;
ii
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o institution of deed restrictions;
o conduct five-year reviews after treatment is completed to
evaluate the necessity of additional remedial actions.
The initial total present worth cost for the selected remedy as
presented in the Feasibility Studies is $3,947,165.
STATUTORY DETERMINATION
The selected remedy is protective of human health and the
environment, complies with Federal and State requirements that
are legally applicable or relevant and appropriate to the
remedial action, and is cost-effective. The remedy utilizes
permanent solutions and alternative treatment technologies to the
maximum extent practicable and satisfies the statutory preference
for remedies that employ treatment that reduces toxicity,
mobility, or volume as a principal element.
Date Patrick M. Tobin, Acting
Acting Regional Administrator
U.S. EPA Region IV
111
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TABLE OF CONTENTS
I. - DECLARATION i
II. DECISION .SUMMARY : . . iv
Table of Contents iv
List of Figures vi
List of Tables vi
1.0 Site Name, Location, and Description 1
2.0 Site History and Enforcement Activities 4
3.0 Highlights of Community Participation 6
4.0 Scope and Role of Operable Unit 7
5.0 Summary of Site Characteristics 8
5.1 Site Topography and Surface Features 8
5.2 Geology 9
5.2.1 Site Soils 9
5.2.2 Surficial Sands 9
5.3 Surface Water Hydrology 11
5.4 Sampling Results 12
5.4.1 Soils 12
5.4.2 Surface Water and Sediments 18
5.4.3 Ash Pile 20
6.0 Baseline Risk Assessment Summary 20
Soils and Sediments
6.1 Site Source Risk Assessment 21
6.1.1 Contaminants of Concern 21
6.1.2 Exposure Assessment 23
6.1.3 Toxicity Assessment 23
6.1.4 Risk Characterization .' 25
Ash Pile
6.2 Ash Pile Risk Assessment 30
6.2.1 Contaminants of Concern 30
6.2.2 Exposure Assessment 31
6.2.3 Toxicity Assessment 31
6.2.4 Risk Characterization 31
6.3 Environmental Risks 32
7 .0 Description of Remedial Alternatives .*. 33
7.1 Alternative No. 1 - No Action 33
7.1.1 Alternative No. 1A - No Action 33
7.1.2 Alternative No. IB - Limited Action .... 34
iv
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TABLE OF CONTENTS (CONT.)
7.2 Alternative No. 2 - Containment 35
7.3 Alternative No. 3 - In-Situ Treatment 41
7 .4 Alternative No. 4 - Ex-Situ Treatment ; . . 47
7.4.1 Alternative No. 4A - Soil Washing 48
7.4.2 Alternative No. 4B - High Temperature
Thermal Desorption 53
7.5 Alternative No. 5 - Off-Site Disposal 57
7.6 Alternative No. 1 - No Action 60
7.7 Alternative No. 2 - S/S and On-Site Disposal .. 61
7.8 Alternative No. 3 - S/S and Off-Site Disposal . 62
8.0 Comparative Analysis of Remedial Alternatives 62
Soils and Sediments
8.1 Overall Protection of Human Health and the
Environment 63
8.2 Compliance with Applicable.,or Relevant and
Appropriate Requirements 65
8.3 Long-Term Effectiveness 66
8.4 Reduction of Toxicity, Mobility, or Volume
Through Treatment 67
8.5 Short-Term Effectiveness 68
8.6 Implementability 69
8.7 Cost 71
8.8 State Acceptance 71
8.9 Community Acceptance 72
Ash Pile
8.10 Overall Protection of Human Health and the
Environment 72
8.11 Compliance with Applicable or Relevant and
Appropriate Requirements 72
8.12 Long-Term Effectiveness 72
8.13 Reduction of Toxicity, Mobility, or Volume
Through Treatment 73
8.14 Short-Term Effectiveness 73
8.15 Implementability 73
8.16 Cost .' 73
8.17 State Acceptance 74
8.18 Community Acceptance 74
9 .0 Selected Remedy 74
9.1 Source Control 74
9.1.1 The Major Components of Source Control
To Be Implemented 75
9.1.2 Performance Standards 76
9.1.3 General Component *. 79
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TABLE OF CONTENTS (CONT.)
10.0 Statutory Determinations 81
10.1 Protective of Human Health and the
Environment 81
10.2 Compliance with Applicable or Relevant and
Appropriate Requirements 81
10 .3 Cost Effectiveness . 83
10.4 Utilization of Permanent Solutions to the
Maximum Extent Practicable 83
10.5 Preference for Treatment as a Principal
Element 83
11.0 Documentation of Significant Changes 84
VI
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LIST OF FIGURES AND TABLES
Figures
Figure 1.1 Site Location Plan 2
Figure 1.2 Site Area Plan 3
Figure 2.1 Site Plan 5
Figure 5.1 Typical Geologic Profile 10
Figure 5.2 Sampling Location Plan 14
Figure 7.1 Plan and Profile of Slurry Wall 38
Figure 7.2 Typical Multimedia Cap 39
Figure 7.3 Typical Profile of Proposed In-Situ Treatment.
System 44
Figure 7.4 Proposed In-Situ Treatment System Plan 45
Figure 7.5 Soil Washing System 50
Figure 7.6 Stabilization Process 52
Figure 7.7 Thermal Desorption 55
Tables
Table 6-1 Exposure Point Concentrations 22
Table 6-2 Exposure Assumptions for Soil, Sediments and
Air Pathways 24
Table 6-3 Toxicity Values for Contaminants of Concern 26
Table 6-4 Summary of Site Risks 28
Table 6-5 Summary of Hazard Quotients .' 29
Table 7-1 Cost Summary of Remedial Alternatives 36
Table 8-1 Glossary of Evaluation Criteria 64
Table 9-1 Remediation Goals for Chemicals of Concern
in Soils 77
Table 9-2 Remediation Goals for Chemicals of Concern *
in Sediments 78
Table 9-3 Solidification Performance Standards 80
vii
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RECORD OF DECISION
Summary of Remedial Alternative Selection
Operable Unit One - Soils, Sediments and Ash
Peak Oil/Bay Drums Superfund Site
Brandon, Hillsborough County, Florida
1.0 Site Name, Location, and Description
The Peak Oil Site (the Site) is located in the north central
section of Hillsborough County, Florida within the southeast
quarter of Section 7, Township 29, South Range 20 East (see
Figure 1.1). The Site is located south of State Road 574
(SR 574) and the CSX Railroad and approximately 0.25 miles west
of Faulkenburg Road (see Figure 1.2).
As shown on Figure 1.2, the Peak Oil Site is approximately four
acres in area (approximately three football fields side by side).
The Site is located between the Reeves Southeastern Wire (SEW)
parcel on the east and the Bay Drums Superfund Site on the west.
The Reeves Southeastern Galvanizing (SEG) Superfund Site is
located north of the Peak Oil Site, across SR 574. Just south of
the Peak Oil Site is a Peoples Gas Company natural gas
distribution center and a pile of discarded roofing materials.
The Site currently has two warehouse-type buildings, a concrete
block office building, a small storage shed, a small lagoon from
which waste oil sludges were excavated during a previous EPA
removal action, a 6,000 cubic-yard ash pile lined and covered
with plastic liners (also from the previous EPA removal action),
and a 400 cubic-yard soil pile. A concrete pad, 90 feet by 110
feet, is also located in the southeast corner of the site.
The closest residential areas to the site are single-family
houses and mobile homes, located approximately 0.3 miles east of
the Peak Oil Site across Faulkenburg Road. Other residential
areas include single-family homes, approximately 0.75 miles north
of the Peak Oil Site across SR 574 on Martin Luther King Avenue;
single-family houses in an area approximately 1.2 miles west of
the Peak Oil property near the intersection of U.S. Highway 301
and SR 574; and single-family residences and mobile homes in an
area approximately 1.8 miles northeast of the Peak Oil property
on Six Mile Creek Road.
Three wetlands are adjacent to the site, to the southwest,
southeast, and northwest. Stormwater runoff drains primarily to
the west, but a small part of the site drains to the southeast.
The southwest corner of the site is subject to inundation during
wet seasons due to the high groundwater table, but is not within
any drainageway flood plain.
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N
STUPY AREA
VICINITY MAP
NOT TO SCALE
REFERENCES:
- USCS. 7.5 WIN. SERIES, BRANDON
QUADRANGLE. flORIDA-HIUSflOROOCH CO..
1956. PHOTOREV1SED 1987.
2.000
2.000 FEET
SfTE LOCATION PLAN
SITE SOURCE CHARACTERIZATION
PEAK OIL SUPERFUND SITE
TAMPA, FLORIDA
FIGURE 1.1
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2.0 Site History and Enforcement Activities
The Peak Oil Facility was constructed and began operation in
August 1954, under the ownership of Mr. John Schroter. Ownership
of the company was transferred in 1975 to Mr. Robert Morris.
Mr. Morris and his sons continued the operation of the business
as a used oil re-refinery. After 1979, operations reportedly
were limited to the resale of used oils as fuel and flotation oil
and repackaging of virgin material.
Facility operations involved the use of a re-refining process to
purify used oils and lubrication fluids. Used oils accepted at
the facility for re-refining consisted primarily of used auto and
truck crankcase oil, with some hydraulic oil, transformer fluid,
and other used oils.
An acid/clay purification and filtration process was used to
re-refine the oil. This process generated a low-pH sludge and
oil-saturated clay, which were stored over the life of the
facility in three separate impoundment areas (Lagoons No. 1,
No. 2 and No. 3) in the southern portion of the site. Sludge
storage Lagoon No. 1 was in use until sometime after 1960.
Another sludge storage area was constructed further south of
Lagoon No. 1. This area consisted of two large, unlined
impoundments measuring approximately 90 feet by 100 feet each
(Lagoon No. 2 and Lagoon No. 3). The two impoundments were
connected by an oil/water separator. The locations of the
lagoons are shown on Figure 2.1.
In approximately late 1979 or 1980, the company discontinued the
re-refining process and shifted to filtering and blending used
oil for resale. Several company employees have reported that
spills and leaks continued to occur from on-site storage tanks,
tanker trucks, oil/water separators, and other on-site equipment
after the company shifted its operations from re-refining to
filtering and blending. The former employees also reported that
some wastes continued to be stored in the on-site lagoons after
the shift to filtering and blending operations.
Lagoon No. 1 and Lagoon No. 3 were backfilled. However,' the
exact dates of backfilling are unknown. Lagoon No. 2 is the only
impoundment on the site that was not backfilled. This lagoon
originally contained up to approximately 12 feet of sludge.
Overflow from Lagoon No. 2 was apparently directed to the
oil/water separator to remove free oil, and the aqueous phase was
discharged into Lagoon No. 3, to the east. EPA and the FDER
conducted inspections at the Peak Oil and Bay Drum Sites and
reported that various chemical constituents were present in site
soils, including heavy metals, petroleum hydrocarbons, trace
concentrations of polychlorinated biphenyls (PCBs), and solvent-
type chemical compounds.
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In 1986, EPA initiated a removal action utilizing a mobile
incinerator to treat approximately 4,000 cubic yards of acidic
polychlorinated biphenyl (PCB) sludge found in Lagoon No. 2.
Approximately 6,000 cubic yards of ash generated during the
incineration process was placed on and covered with a protective
plastic cover at the Site.
In 1984, the Peak Oil and Bay Drums Sites were jointly evaluated
according to the Hazard Ranking System and proposed for listing
on the National Priority List (NPL) with a score of 58.15. On
June 10, 1986, the Peak Oil Site, combined with the adjacent Bay
Drums Site, was placed on the NPL. In 1989, members of the Peak
Oil Generators Group entered into a Consent Order with the EPA to
conduct a remedial investigation/feasibility study (RI/FS) at the
Peak Oil Site.
3.0 Highlights of Community Participation
In accordance with Sections 113 and 117 of CERCLA, EPA has
conducted community relations activities.at the Peak Oil Site to
ensure that the public remains informed concerning activities at
the site. During the numerous removal activities at the site,
EPA issued press releases to keep the public informed. There was
some local press coverage of EPA's activities, and EPA held
meetings with local (county) and state officials to advise them
of the progress at the site.
A community relations plan (CRP) was developed in 1988 and
revised in 1989 to establish EPA's plan for community
participation during remedial activities. Following completion
of the RI/FS, a Proposed Plan fact sheet was mailed to local
residents and public officials on August 12, 1992. The fact
sheet detailed EPA's preferred alternative for addressing the
source of contamination (Operable Unit One) at the Peak Oil Site.
Additionally, the Administrative Record for the site, which
contains site related documents including the RI and FS reports
and the Proposed Plan, was made available for public review at
the information repository in the Brandon Public Library. A
notice of the availability of the Administrative Record for the
Peak Oil Site was published in the Tampa Tribune on
August 11, 1992 and again on August 17, 1992.
A 30-day public comment period was held from August 13, 1992 to
September 13, 1992 to solicit public input on EPA's preferred
alternative for Operable Unit One. Finally, EPA held a public
meeting on August 18, 1992 at the Hillsborough Community College
to discuss the remedial alternatives under consideration and to
answer any questions concerning the proposed plan for the Site.
EPA's response to each of the comments received at the public
meeting or during the public comment period is presented in the
Responsiveness Summary which is provided in Appendix A of this
ROD.
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A second fact sheet and Proposed Plan were generated for the ash
pile located on the Peak Oil Site, since it was not discussed
during the first group of community relations activities. The
Proposed Plan was mailed out to concerned parties in February,
1993, notifying them of the selected remedy of treatment of the
ash pile. A public meeting was held on February 24, 1993 in the
Brandon Regional Library enabling concerned citizens to voice
their opinions and obtain answers to questions which they might
have. The public comment period occurred from February 20, 1993
to April 21, 1993. Announcements were placed in the Tampa
Tribune on February 18, 1993 and February 23, 1993 which notified
the public of the availability of the Administrative Record at
the Brandon Regional Library.
This decision document presents the selected remedial action for
the Peak Oil Site in Brandon, Florida, chosen in accordance with
CERCLA, as amended by SARA, and to the extent practicable, the
NCP. This decision is based on the Administrative Record for the
site.
4.0 Scope and Role of Operable Unit
As with many Superfund sites, the problems at the Peak Oil/Bay
Drums Site are complex. As a result, EPA has divided the remedy
for the Site into four operable units (OUs) . These are:
o OU One: Contamination in the soils, sediments and ash
pile at the Peak Oil Site;
o OU Two: Contamination in the groundwater at the
Peak Oil and Bay Drums Sites;
o OU Three: Contamination in the soils and sediments
at the Bay Drums Site;
o OU Four: Contamination in the Wetlands at the
Peak Oil, Bay Drums, and Reeves
Southeastern Sites.
The remedial actions for OUs Two, Three and Four will be
addressed in separate RODs.
OU One is addressed in this ROD. Potential direct contact with
soils, sediments and ash and potential ingestion of groundwater
contaminated above MCLs pose the principal threats to human
health at the Peak Oil Site. The purpose of the remedy selected
in this ROD is to prevent current or future exposure to
contaminated soils, sediments and the ash pile and to prevent
current or future migration of contaminants to the groundwater.
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5.0 Summary of Site Characteristics
The climate in the Tampa area is characterized by mild winters
and relatively long, humid, and warm summers. Spring and fall
tend to be dry, with the majority of the rainfall falling in the
summer.
5.1 Site Topography and Surface Features
The topography of the Peak Oil Site is relatively flat with three
ponded areas and a lagoon. Surface elevations at the site have
changed in the past year due to regrading by EPA's removal
contractor but generally vary from about 39 feet to 42 feet mean
sea level (MSL). Due to. the site's elevation above MSL, tidal
surges are not likely to impact the area. The surface slopes
from the eastern to the western border of the site. Near the
southern portion of the site, however, the soil surface slopes to
the south.
As shown on Figure 2.1, Lagoon No. 2 is located in the southwest
portion of the Peak Oil Facility. The three ponded areas are in
the northwest sector of the property, adjacent to the two large
warehouse buildings. The two depressions along the northern
boundary of the property were formerly one continuous swale which
has been divided at its midpoint by an earthen berm. These
northern depressions retain standing water only during the rainy
seasons or after heavy rainfall events. The pond in the
northwest corner of the property is surrounded by thick
vegetation. Because of the depth of this depression relative to
the water table, water generally exists in this pond on a
continuous basis and is approximately two feet deep. The pond
which previously existed on the south side of the northwest
building (Figure 2.1) was backfilled by the EPA removal action
contractor in early 1991 before the Phase 2 investigation.
Currently, an ash pile of approximately 6,000 cubic yards, which
was generated during EPA's removal action, is sitting on and
covered with a plastic liner in the northeast portion of the Peak
Oil Facility. EPA also constructed a concrete pad on the
southeastern portion of the site as part of the incineration
removal action. Although the southern part was later removed,
approximately 7,000 square feet of the original pad still remain.
Approximately 400 cubic yards of soil which were stockpiled on
the Peak Oil Site during EPA's 1990 and 1991 Bay Drums and Peak
Oil removal actions currently remain south of the large warehouse
building.
As shown on Figure 2.1, four structures remain on-site. These
are the two large sheet-metal warehouse buildings in the
northwest corner of the site, a one-story concrete block office
building just south of the warehouses, and a small storage shed
south of the ash pile.
8
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The site is surrounded by a chain-link fence and access is
limited to two locked gates, one on the north property line and
one near the southeast corner of the property.
Land use in the area is either industrial or undeveloped, with
the nearest single family residential area being 0.3 miles east
of the Peak Oil Site. It is anticipated that the primarily
industrial character of the area surrounding the site will be
maintained in the future.
5.2 Geology
5.2.1 Site Soils
The soils immediately underlying the Peak Oil Site are separated
into two basic units: the surficial sands and the low-
permeability unit of the upper Hawthorn Group (Figure 5.1).
Although the composition of the surficial sand and low-
permeability unit varies across the site, the two basic units are
present.
" 5.2.2 Surficial Sands
The undifferentiated surficial sand unit varies in thickness from
approximately 9 to 23 feet at the Peak Oil Site and from 9 to 37
feet in the study area, as determined by the Area-Wide Hydrologic
RI (Canonie, 1992) . Constituting the uppermost soil unit on the
site, it consists primarily of poorly graded fine sands with
varying amounts of silt. These sands are primarily brown in
color, but occasional lenses of gray sand are encountered. The
standard penetration numbers (or N Values) generally range
between 5 and 30 blows per foot. Correlation of the N Values to
the relative density of the soils indicates that most of the
surficial sands are loose to medium in density.
The Unified Soil Classification System (USCS) soil types of the
surficial sands are generally gravelly sands (SP) or gravelly to
silty sands (SP-SM). In a few isolated instances, trace amounts
of clay are found in the sand unit, resulting in only a slight
degree of cohesiveness to the soil.
Water content in the saturated zone of the surficial sands ranges
from 15 to 20 percent, while water content in the vadose zone is
generally less than 10 percent. Groundwater was typically
encountered at depths ranging from two to four feet. Surficial
sand samples tested for pH exhibited values between 5.0 and 8.0.
Laboratory constant-head permeability tests conducted on
surficial sand samples resulted in hydraulic conductivity (K)
values in the 10"2-to-10"3-cm/sec range. Additional information
on the physical soil test results is contained in the Area-Wide
Hydrologic RI (Canonie, 1992).
In the lower portion of the sand unit, the clay and silt fraction
appears to increase as the low-permeability unit of the upper
Hawthorn Group is approached.
-------
GROUND SURFACE
FORMATION
UNOIFFERENTIATED
SAND DEPOSITS
HAWTHORN
TAMPA
LIMESTONE
OVERLYING
SUWANNEE
LIMESTONE
GENERAL UTHOLOGY
PREDOMINANTLY FINE SANO;
INTERBEODEO CLAY. MARL.
SHELL. LIMESTONE. PHOSPHORITE
GREEN. BLUE. AND CRAY CLAYEY
SANO AND CLAY; LIMESTONE NEAR
BOTTOM Of FORMATION IS WHITE TO
CRAY. SOFT. SANDY. AND POROUS;
FORMATION GENERALLY CONSISTS
OF A BASAL CALCAREOUS UNIT.
A MIDDLE CLASTIC UNIT. AND
AN UPPER UNIT OF CLASTIC
AND CARBONATE ROCK AND SOIL;
MIDDLE AND UPPER PARTS
CONTAIN MORE PHOSPHATE
THAN LOWER CALCAREOUS UNIT
(NOTE: UPPER PART OF TAMPA
FORMATION IS RELATIVELY HIGH
IN CLAY CONTENT MAKING CONTACT
BETWEEN TAMPA AND HAWTHORN
DIFFICULT TO DETERMINE.)
WHITE. CREAM. AND CRAY, HARD
TO SOn. SANDY LIMESTONE:
SANDY. PHOSPHATIC. FOSSILIFEROUS
WITH CHERT LENSES; SANO AND
CLAY IN LOWER PART IN SOME
SECTIONS: MANY MOLDS OF
PELECYPODS AND GASTROPODS.
WHITE, YELLOW AND LIGHT BRQWN.
SOFT TO HARD DENSE, FINE-
GRAINED LIMESTONE WITH CHERT
LENSES TO 25 FEET THICK;
FOSSILIFEROUS.
I SAND
CLAY
CLAYEY
li ' i ' i 'I LIMESTONE
PHOSPHATIC NODULES
CHERT
CALCAREOUS UNIT
cm
TYPICAL GEOLOGIC PROFILE
SITE SOURCE CHARACTERIZATION
PEAK OIL SUPERFUND SITE
TAMPA. FLORIDA
FIGURE 5.1
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The second major unconsolidated sedimentary unit is the low-
permeability unit underlying the Peak Oil Site. The low-
permeability unit is a component of the upper Hawthorn Group
(Figure 5.1). The two basic characteristics of the low-
permeability unit which distinguish it from the overlying sands
are clay content and color. Thus, the surface of the low-
permeability unit is generally determined by.the contact between
the silty sands of the surficial sand unit and the clayey sands
and clays of the low-permeability unit. The color change from
the predominantly brown sands to the green, blue, and gray clayey
soils below is another distinguishing characteristic of this
transition.
i
In contrast to the sands and silty sands in the overlying soil
unit, the soils in the low-permeability unit generally contain
sufficient quantities of clay to result in cohesiveness. In
general, the soils may be classified as clayey sand (SC in the
USCS) or sandy clay (CL or CH in the USCS) . The SC soils., or
clayey sands, generally contain between 25 and 50 percent fines
which possess a significant degree of plasticity. Hydraulic
conductivities in the SC soils are in the range of 10"s to
10"6 cm/sec. The CL and CH soils are dominated by plastic fines
with varying degrees of plasticity. The majority of clay
specimens which were laboratory tested for geotechnical
parameters are high-plasticity clays, or CH soils, with liquid
limits greater than 50 percent and which plot above the A Line on
the USCS Plasticity Chart. Hydraulic conductivities in the CL
and CH soils are in the range of 10'6 to 10"9 cm/sec.
The SC, CL, and CH soils are characteristically green, blue, or
gray or a combination of these shades. Brown clayey soils are
sometimes encountered, but their occurrence is less frequent than
the green-, blue-, and gray-colored soils.
5.3 Surface Water Hydrology
Due to the flat topography of the site and the porous nature of
the sandy surficial soils, runoff generally occurs only during
and after heavy precipitation events. During moderate
precipitation events, the majority of rainfall immediately
percolates into the soils or flows to localized depressions where
it evaporates or percolates. This section discusses the drainage
patterns of runoff which occur during heavy rainfall. The
discussion presented in this section is based on field
observations and knowledge of the site topography after regrading
activities conducted by the EPA.
Currently, runoff from the southwestern portion of the Peak Oil
Site drains into the excavated depression of Lagoon No .'2, where
it percolates into the water table. During the rainy season,
Lagoon No. 2 sometimes overflows its banks and the land southwest
of the site floods. During these periods, the area extending
11
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from Lagoon No. 2 to the railroad spur on the west and the
Peoples Gas fenceline on the south is flooded.
Runoff from the southeastern portion of the site drains to the
soufeh into the cul-de-sac at the end of Reeves Road or into a
roadside drainage ditch which begins at the western terminus of
Reeves Road and slopes east. Water which enters this ditch-may
flow east along Reeves Road for approximately 400 feet and then
passes south underneath the road via a culvert. After exiting
this culvert, runoff stands and percolates in a small depression
and areas of heavy vegetation south of Reeves Road.
\
Following EPA's regrading of the site in 1991, surface water
runoff from the north-central portion of the site flows west
toward the railroad spur along the west side of the site. During
Phase 2 of the RI, Canonie installed a silt fence along the
western site boundary to prevent off-site transport of sediment.
Surface water runoff from the extreme northern portion of the
Peak Oil Site drains to the north into the depressions at the
northwest corner of the Peak Oil property. A portion of the
runoff may flow across the unpaved road which borders the north
side of the Peak Oil Site and into the ditch to the immediate
north (see Figure 1.2). This ditch parallels the southern side
of the CSX Railroad. A culvert exists beneath the railroad and,
at one time, apparently provided a connection from the ditch on
the south side to the ditch on the north side. However,
reconnaissance conducted by Canonie during the Phase 1 field
investigation revealed that this culvert is buried by dry
sediment, and there was no visible flow through this conduit.
Water in the ditch on the north side of the railroad flows north
under SR 574 via a culvert and into the North Wetland.
5.0 Sampling Results
During the site source RI, soil, surface water, and sediment
samples were collected at the site to determine the extent and
nature of contamination. The RI also investigated the extent of
impact of the contamination and the volume of material requiring
cleanup.
Also, in a separate study, samples were collected to determine
the characteristics of the ash pile located at the northeast
corner of the site.
5.4.1 Soils
Sampling data indicates that site soils contain various organic
and inorganic constituents throughout the former lagoon*areas and
the area south of the ash pile. Volatile organic compounds
12
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(VOCs), semi-volatile organic compounds, polychlorinated
biphenyls (PCBs), and high concentrations of metals are found
primarily in the upper eight feet of soil.
The-most prevalent VOCs in site soils are toluene, ethylbenzene,
and xylene. These constituents are present in Former Lagoon
No. 1 and southwest of the ash pile. Chlorinated organic
compounds were also detected in a small area of soils southwest
of the ash pile and other localized areas. Polycyclic aromatic
hydrocarbons (PAHs), most notably naphthalene, were also present
primarily in an area extending from the northeast portion of the
site southwesterly toward Lagoon No. 2. Various inorganic
constituents were found in site soils with the primary metals
impact associated with lead. Lead was present at concentrations
above background in an area encompassing the former lagoons and
stretching northwesterly toward the railroad spur. PCBs were
found only in the area within and east of Former Lagoon No. 1.
A visible oily residue exists over the entire thickness (about 12
feet) of surficial sand in the area of Former Lagoons No. 1 and
No. 3 containing total petroleum hydrocarbons (TPHs) at
concentrations of up to five percent at idepths of 4.0 to 6.0
feet. Based on analytical testing and visual assessment, the
major impacts of contamination on the soils at the site are
related to waste oils and inorganic constituents (metals).
Volatile Organic Compounds in Soil
Twenty VOCs were detected in site soils (Figure 5.2 illustrates
sampling locations). The most frequently detected VOCs were
toluene (detected in 49 samples), xylenes (detected in 36
samples), and acetone (detected in 35 samples). Other VOCs
detected in 20 or more samples include tetrachloroethene (PCE)
and ethylbenzene.
The VOC with the maximum detected concentration was total xylenes
[with concentrations ranging from 0.002 parts per million (ppm)
to 94 ppm]. Xylenes were primarily found in Former Lagoon No. 1
and in the upper soils (0.0 to 8.0 feet) southwest of the ash
pile. The highest concentration was found in Sample L9#2, which
was collected at a depth of 10 to 12.5 feet in Former Lagoon
No. 1. However, Sample L9#2 was the only sample in the lower
soils (8.0 to 21.0 feet) that contained concentrations of total
xylenes greater than 1.0 ppm.
V
PCE, the VOC with the second highest concentration (25 ppm), was
primarily found in the area just southwest of the ash pile. As
with xylenes, PCE was primarily found in the upper soils in this
area. Samples G4#l and E7#l, which are located in this*area,
contained 25 ppm and 21 ppm of PCE, respectively. No other soil
samples on-site contained PCE at levels greater than 1 ppm.
13
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U^Ur
rtNCi
— ~~ ONlUPBOVtD
— •* OW»IACt OtIC
CMC Or "OOOtO »RtA
UAR3H
PK*St I SU»f»CC ««tt»/SCO
-------
Ethylbenzene and toluene, the VOCs with the next highest
concentrations (both were detected at 20 ppm), were generally
found in the same locations as xylenes.
The-highest concentrations of benzene (1.8 ppm), vinyl chloride
(0.57 ppm), and trichloroethene (TCE) (2.7 ppm) were also
detected in samples obtained from the soils south of the ash
pile. The highest concentrations of three other VOCs were found
in Boring L3, which was drilled through the concrete pad
remaining from EPA's removal action of Lagoon No. 2 sludge.
1,1-Dichloroethane (1,1-DCA) (3.5 ppm), 1,1,1-trichloroethane
(1,1,1-TCA) (14 ppm), and methylene chloride (1.3 ppm) were
detected in the upper sample from this boring.
In summary, VOCs were primarily found in soils less than eight
feet deep with toluene, ethylbenzene, and xylenes being the most
prevalent. These compounds were found primarily in Former Lagoon
No. 1 and in the area southwest of the ash pile. Chlorinated
organics were also detected in the area of soils southwest of the
ash pile, beneath the concrete pad, and at low levels in other
localized areas.
Semivolatile Organic Compounds in Soil
Twenty-seven SVOCs were detected in site soils, including several
PAHs. The most frequently detected SVOCs were (in order of
decreasing frequency of detection) phenanthrene, fluoranthene,
pyrene, naphthalene, benzo(b)fluoranthene, and
benzo(g,h,i)perylene. These compounds were detected in 26 to 37
samples of the 82 samples analyzed.
The highest concentration detected among the SVOC compounds was
65 ppm naphthalene (detected in Sample G4A#1), which was detected
primarily in soils shallower than 8.0 feet in the area just south
of the ash pile and in the former lagoons. Other SVOCs detected
at concentrations over 10 ppm included acenaphthylene (16 ppm),
anthracene and phenanthrene (both at 15 ppm), and fluoranthene
(10 ppm).
As indicated in the Baseline Risk Assessment (RA) for the site,
naphthalene is considered to be noncarcinogenic. Other PAHs
which are considered to be noncarcinogens are acenaphthylene,
acenaphthene, anthracene, benzo(g,h,i)perylene, fluoranthene,
fluorene, 2-methylnaphthalene, phenanthrene, and pyrene. As with
naphthalene, the total noncarcinogenic PAH concentrations are
found primarily in the upper soils (0.0 to 8.0 feet) in an area
stretching from the east boundary of the site just southeast of
the ash pile toward the lagoon areas.
«•
The PAHs which are considered in the RA to be potential
carcinogens are benzo(a)anthracene, benzo(a)pyrene,
15
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benzo(b)fluoranthene, benzo(k)fluoranthene, chrysene,
dibenzo(a,h)anthracene, and indeno(l,2/3-c,d)pyrene.
A concentration of benzo (a) anthracene over 1.0 ppm was only
detected in Boring Fl, near the east boundary of the site just
southeast of the ash pile. This sample was taken at a depth of
2.0 to 6.0 feet. Total carcinogenic PAH concentrations greater
than 1.0 ppm were detected only in Boring L9, which was drilled
in Former Lagoon No. 1, and Boring F-l near the east side of the
property.
In summary, various SVOCs, including PAHs, were detected in site
soils. As with VOCs, PAHs were found primarily in soil shallower
than 8.0 feet. The distribution of PAHs is somewhat different
than the distribution of VOCs. PAHs were found in an area
stretching from a point along the eastern fenceline just
southeast of the ash pile, southwest toward Lagoon No. 2.
Organochlorine Pesticides and Polvchlorinated Biphenvls in Soil
The only pesticide compound detected was .alpha-BHC, which was
detected at 0.014 ppm in Sample J9A#2. Seven different PCBs were
detected in soil samples. Aroclor-1260 was detected in 28
samples with concentrations ranging from 0.035 ppm to 110 ppm.
Aroclor-1260 concentrations over 50 ppm were detected in only two
samples. These are Sample K4#l (110 ppm), which was taken east
of Former Lagoon No. 1 adjacent to the concrete pad at a depth of
2.0 to 4.0 feet, and Sample L9#2 (52 ppm), taken in Former Lagoon
No. 1 at a depth of 10.0 to 12.5 feet. All other PCB Aroclors
were detected in five or fewer samples, with the highest
concentration detected at 6.6 ppm.
Based on the soil boring sample analysis and past investigations
of the site, PCBs were detected primarily in the historical
lagoon areas.
Inorganic Constituents in Soil
Many inorganic constituents in soil samples are naturally
occurring in the environment. To focus the following discussion
on inorganic constituents which may be of concern, the detected
concentrations have been compared to ranges of background
concentrations in soils near the Peak Oil, Reeves, and Bay Drums
sites. Based on this comparison and consideration of the
relative toxicity of the constituents (as ranked in the Baseline
Risk Assessment (RA)) , the inorganics which may be of concern or
were detected above background levels are discussed below,
beginning with the chemicals detected at the highest
concentrations.
f
Lead; Lead was detected in 77 of 82 samples with concentrations
ranging from 1.1 ppm to 2,950 ppm. Background concentrations of
lead in the area are <50 ppm. The highest concentrations of lead
16
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were detected in the former lagoon areas, especially the Former
Lagoon No. I area, where two concentrations above 1,000 ppm were
found. Former Lagoon No. 3 is also impacted with concentrations
of lead above 500 ppm. Generally, soils in the shallow depth
interval (0.O-to-8.0-foot depth) contain higher concentrations of
lead than the deeper interval (8.O-to-21.0-foot depth). The RA
identified lead as an indicator chemical.
Zinc: Zinc concentrations were detected in 81 of the 82 samples,
ranging from 1.5 ppm to 2,410 ppm (L9#l). Background
concentrations of zinc in the area are <29 ppm. The area of
zinc-impacted soil is similar in distribution to that of many
site contaminants. Zinc was detected up to 2,410 ppm in the
lagoon areas and in the region just south of the ash pile. Zinc
concentrations in the lower interval near former Lagoon No. 3
were higher than in the upper interval. Concentrations of zinc
up to 1,830 ppm were also detected along the eastern border of
the site.
Barium: Barium was detected in 69 of 82.samples at
concentrations from 0.61 ppm to 460 ppm (L9#2). Concentrations
" above the background range (<51 ppm) were limited to the former
lagoon areas (460 ppm), the concrete pad area (152 ppm), and some
areas around the warehouse building (155 ppm) . Barium was
identified as an indicator chemical during the RA.
Chromium: Chromium was detected in 74 of 82 samples at
concentrations ranging from 1.2 ppm to 104 ppm (N9A#2).
Background concentrations of chromium in the area are <18 ppm.
Concentrations near the higher end of the detected concentration
range are located sporadically across the site, without any
regular pattern of occurrence. Additionally, the locations of
the higher concentration detections were not the same as other
known site contaminants (i.e., higher concentrations found below
8.0 feet deep with lower concentrations in shallower soil).
Therefore, chromium detected at the site may be naturally
occurring and not the result of site activities.
Several additional inorganic elements were detected in former
lagoon areas above background levels. These elements include
arsenic, beryllium, cadmium, copper, manganese, and mercury.
Other inorganic constituents detected above background levels
include cobalt, which was found in the central portion of the
site; cyanide, which was detected in the north-central portion of
the site near Borings E7 and F9; and silver, which was found in
the central site area and Former Lagoon No. 1 vicinity.
Generally, concentrations of inorganic constituents were detected
in the Former Lagoons No. 1 and No. 3 areas and the area
extending northwest from Lagoon No. 1. Also impacted is the soil
south of the ash pile. Soils in the lower interval (8.O-to-21.0-
foot soil depth) were less impacted than the upper interval;
17
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however, the lower interval soils, especially in the lagoon
areas, do contain concentrations above background.
5.4.2 Surface Water and Sediments
Surface water and sediment samples were obtained from the ponded
areas located in the northwest corner of the Peak Oil Site and
from Lagoon No. 2. The results are discussed below. Figure 5.2
shows the sampling locations. It should be noted that the pond
from which Samples PK-5 and PK-6 were taken during Phase 1 was
filled in prior to Phase 2 and no longer exists.
5.4.2.1 Chemical Constituents Detected in Surface Water
Three VOCs were detected: acetone, carbon disulfide, and total-
1,2-dichloroethylene. Acetone was detected in Sample PK-1R at
0.005 ppm and Sample PK-3R at 0.007 ppm. Total-1,2-
dichloroethylene was detected in Sample PK-1R at 0.002 ppm and
Sample PK-2R at 0.003 ppm. Carbon disulfide was detected in
Sample PK-2R at 0.001 ppm. No VOCs were.detected in Lagoon
No. 2.
Nine SVOCs were detected at very low levels, five of which are
PAHs. Concentrations of the PAHs, which were all detected in
samples from Lagoon No. 2, are all in the parts-per-trillion
(ppt) range. Based on the SVOC data from the five surface water
samples, the pond water impacts appear to be minimal.
No PCBs were detected in surface water samples obtained on-site.
V
Seventeen metals and cyanide were detected in the surface water
samples. Samples PK-5 and PK-6R, which were collected from the
former pond south of the large warehouse building, contained the
highest concentrations of all but three analytes (antimony,
cyanide, and magnesium). This pond was filled in during recent
EPA removal actions.
In the surface water remaining at the site, concentrations of
three metals exceed EPA chronic Ambient Water Quality Criteria
(AWQC) for the protection of aquatic organisms. These metals are
silver (AWQC of 0.00012 ppm), zinc (AWQC of 0.047 ppm), and lead
(AWQC of 0.0032 ppm). The AWQC for silver and zinc are exceeded
only at Samples PK-1, PK-2, and PK-3, which were taken in the
ponded areas in the northwest corner of the site. The AWQC for
lead is exceeded at all surface water sample locations.
5.4.2.2 Chemical Constituents Detected in Sediments
Nine VOCs were detected in site sediment. The highest detected
concentrations were 120 ppm total xylenes and 23 ppm
ethylbenzene, detected in Sample PK-3 from the ponded area north
of the large warehouse building. All other VOCs detected in
I
18
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on-site sediment samples were found at concentrations below
1 ppm.
Although all sediment samples contained at least one detectable
concentration of a VOC, the sample from the pond area north of
the large warehouse building contained concentrations of
ethylbenzene (23 ppm), xylenes (120 ppm), and toluene (0.42-ppm),
and Lagoon No. 2 contained only 0.04 ppm each of PCE and TCE, and
0.48 ppm of toluene.
Twenty-eight SVOCs were detected in sediment at the site. Of the
compounds detected, 15 are PAHs. Pyrene was the most frequently
detected PAH, detected in six samples at concentrations ranging
from 0.21 ppm to 0.62 ppm. Bis (2-rethylhexyl)phthalate was the
most frequent non-PAH compound detected (detected in five
samples). It is also the SVOC with the highest detected
concentration (220 ppm in Sample PK-4). Other detections of
bis(2-ethylhexyl)phthalate were just above 1 ppm. Aside .from
this chemical, all other detected SVOC concentrations in
sediments from ponded areas remaining at.the site are below 1
ppm.
Generally, PAHs were detected at the highest concentrations in
Lagoon No. 2, although the ponded area northeast of the small
warehouse building is also impacted, especially with other
semivolatiles.
Aroclor-1260 was detected in seven of the eight sediment samples.
However, at least one of the PCB Aroclors was found in each
sediment sample. Sample PK-3, collected from the pond north of
the large warehouse, contained the highest concentration of
Aroclor-1260 in sediment at 37 ppm.
The following inorganic constituents were detected in sediment
above the background levels or are of concern at the site.
Lead: Lead was detected above background (50 ppm) in all eight
sediment samples. Concentrations were highest (1,450 ppm) in the
pond west of the warehouse building. The lowest concentrations
detected (152 ppm) were in the former pond, which, as mentioned
earlier, was backfilled during the EPA removal action.
Zinc: Zinc was detected in all sediment samples at
concentrations above background (29 ppm) . The greatest
concentration (918 ppm) was detected in the pond north of the
warehouse building (PK-3). Other high concentrations (445 ppm
and 559 ppm) were detected in the pond west of the warehouse
building.
v
Other inorganic constituents which were detected above naturally
occurring concentrations include antimony, barium, copper,
cyanide, and manganese. Concentrations of these analytes were
19
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generally limited to the pond west and the pond north of the
warehouse building.
In summary, concentrations of some inorganic constituents were
detected above naturally occurring levels in all of the on-site
pond sediments. However, the highest concentrations were
generally limited to the pond west and the pond north of the
warehouse building.
5.4.3 Ash Pile
Four discrete samples were collected from the ash pile. The
sampling locations were based on the locations of existing holes
in the protective cover resulting from previous sampling
activities by the Agency for Toxic Substances and Disease
Registry (ATSDR). Because these existing holes were spread
evenly over the pile, no additional holes were made in the
protective cover. Samples were collected using hand augers at
depths below the ash pile surface at 18 to 48 inches. Continuous
monitoring during sampling activities with an organic vapor
analyzer(OVA), photoionization detector (HNu), and radiation
meter yielded no response above background conditions. Material
collected for the samples was dark black, fine grained and
homogeneous in appearance.
Samples were analyzed for TPHs, metals, extractable organic
compounds, pesticide/PCB compounds and purgeable organic
compounds. Total concentrations of lead in the samples ranged
from 2,500 to 5,600 mg/kg. TPH concentrations ranged from 400 to
3,000 mg/kg. Toxicity Characteristic Leaching Procedure (TCLP)
metals, TCLP extractable organic compounds, TCLP pesticides/PCB
compounds, TCLP purgeable organic compounds and TCLP dioxins/
furans were also analyzed. Concentrations of barium in the TCLP
extracts ranged from 0.19 to 0.26 mg/1 and concentrations of
cadmium in the TCLP extracts ranged from 0.058 to 0.074 mg/1,
which are below regulatory levels. Concentrations of lead in the
TCLP extracts exceeded the toxicity characteristic regulatory
level of 5 mg/1 in all four samples, with concentrations ranging
from 26 to 31 mg/1. No regulated semi-volatile, pesticide/PCB
compounds, or dioxin/furan contaminants were detected in the TCLP
extracts.
6.0 Baseline Risk Assessment Summary
The baseline risk assessment provides the basis for taking action
and indicates the exposure pathways that need to be addressed by
the remedial action. It serves as the baseline indicating what
risks could exist if no action were taken at the site. This
section of the ROD reports the results of the baseline risk
assessment conducted for this site.
20
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Generally, EPA evaluates site risks for all environmental media
in one risk assessment and determines cumulative risk based on
total exposure. However, due to the close proximity of the Bay
Drums, Peak Oil and Reeves Southeastern sites, EPA is evaluating
risks posed by groundwater exposure from all three sites in a
separate Area-Wide Groundwater RI/FS and Baseline Risk
Assessment. Since the soils, sediments, and surface waters-
evaluated in this study are a source for the groundwater
contamination, the impact on groundwater is discussed briefly in
this risk summary.
EPA conducted a separate risk assessment of the ash pile to
determine human health risks and what risk based cleanup levels
should be. The risk assessment was based on data from the four
discrete samples collected from the ash pile. The ash pile risk
assessment is discussed in Section 6.2.
6.1 Site Source Risk Assessment
6.1.1 Contaminants of Concern
Specific chemicals of concern were selected if the results of the
risk assessment indicated that a contaminant might pose a
significant current or future risk or contribute to a cumulative
risk which is significant. The criteria for a significant risk
was a carcinogenic risk level within or above the acceptable risk
range, i.e. 1 x 10"4 to 1 x 10"6, or a hazard quotient greater
than 0.1. The contaminants of concern in soils are beryllium,
benzo(a)pyrene, dibenzo(a,h)anthracene, lead and PCBs. The
sediment contaminants of concern are lead and PCBs. The ash pile
contaminant of concern is lead. The air contaminants of concern
are PCBs and tetrachloroethene. The surface water exposure
pathway did not produce any significant risk levels.
The exposure point concentrations, with the exception of lead,
are based on the 95% upper confidence limit (UCL) of the
arithmetic average. Because of the input requirements for the
Biokinetic/Uptake lead model, which was used to evaluate site
lead exposure, the exposure concentrations reflect an arithmetic
average concentration rather than a UCL. The soil UCLs'are based
on1 the uppermost sample from each boring. For this assessment
all surface water bodies are assumed equivalent in their
likelihood for exposure, therefore separate exposure
concentrations were not determined for each water body. Air
models were used to determine the potential airborne
concentrations which could be released from contaminated soil.
The exposure point concentrations for the site contaminants of
concern are contained in Table 6-1.
«•
Currently, site operations have been discontinued. Although
on-site groundwater is not being used at the present time, it is
classified as a Class II aquifer and therefore is a viable source
21
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Table 6-1
Exposure Point Concentrations
Chemical
Concentration
Soil and Sediment
Beryllium
Benzo(a)pyrene
Dibenz(a, h)anthracene
Lead?
FCBs*3
Surface
0.3
JD.6
0.2
352
10
Sediment
NA
NA
NA
1112
38
Air fug/cubic meter)
PCBs0
Tetrachloroethene
Trespasser
8.6E-3
9.5E-2
Worker
5.0E-3
2.9E-2
Resident
5.0E-3
2.9E-2
NA Notation indicates that these chemicals were carried
through the risk assessment but did not produce risks at
levels of concern.
a Due to the requirements of the lead DBK model, the lead
concentrations reflect the arithmetic mean rather than
the 95% upper confidence limit.
" The PCB concentration represents the summation of the
following aroclors; 1016, 1242, 1248, 1254 and 1260.
c The air concentration represents a concentration modeled
from soil levels. The concentrations are averaged over
the exposure period for each scenario, i.e. nine y~ears
for the trespasser and 30 years for the worker and
resident.
22
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of groundwater for future consumption. [The risks associated
with exposure to groundwater are addressed in the Area-Wide
RiskAssessment (Canonie, 1992).] The site is located in an area
which is zoned for industrial uses. Zoning changes would have to
occur before the site could be developed for residential
purposes.
6.1.2 Exposure Assessment
The current exposure pathway which was evaluated was for a
hypothetical trespasser scenario. For this scenario it was
assumed that an individual trespassing on the site is exposed to
chemicals in the soil and the ash pile through the dermal
absorption and ingestion exposure routes. Exposure was assumed
to occur to chemicals in the surface water and sediments of the
site water bodies through wading activities. The assumed
exposure routes for this scenario are dermal absorption of
chemicals in the surface water and sediments and incidental
ingestion of the sediments. Exposure to site contaminants may
also occur via the inhalation exposure route. The trespasser was
assumed to be between the ages of 6 and 15. Exposure assumption
for the trespasser scenario are contained on Table 6-2.
Two potential future scenarios, industrial and residential, were
evaluated. The exposure routes evaluated for the industrial
scenario were incidental ingestion and dermal contact with
surface soil and ash pile sediments, and incidental ingestion of
sediments and dermal contact with surface water and sediments.
On-site workers may also be exposed to airborne contaminants.
Potential exposure pathways evaluated for the potential future
on-site resident were: direct contact with and ingestion of site
soils for an adult and child and inhalation of vapors. Exposure
assumptions for the future exposure pathways are summarized in
Table 6-2.
6.1.3 Toxicity Assessment
Slope factors (SFs) have been developed by EPA's Carcinogenic
Assessment Group for estimating lifetime cancer risks associated
with exposure to potentially carcinogenic contaminants of
concern. SFs, which are expressed in units of (mg/kg-day)"1, are
multiplied by the estimated intake of a potential carcinogen, in
mg/kg-day, to provide an upper-bound estimate of the excess
lifetime cancer risk associated with exposure at that intake
level. The term "upper bound" reflects the conservative estimate
of the risks calculated from the SF. Use of this approach makes
underestimation of the actual cancer risk highly unlikely. Slope
factors are derived from results of human epidemiological studies
23
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Table 6-2
Exposure Assumptions for Soil, Sediment and Air Pathways
Parameter
Current Scenario
Trespasser
(Soil)
Trespasser
(Sediment)
Ingestion Rate (rag/event) 100
Exposure Frequency (dy/yr) 20
Exposure Duration (yr) 9
Body Weight (kg) 35
Exposed Skin Area (cm2) 2130
Adherence Factor (mg/cnr) 0.2
Absorption Rate (metals) (%) 0.1
Absorption Rate (organics) (%) 1
Exposure Time (hr/dy) 8
100
4
9
35
1520
0.2
0.1
- 1
4
Future Scenarios
Parameter
Worker
(Soil)
Worker
fSedimentV
Ingestion Rate (mg/event) 50
Exposure Frequency (dy/yr) 220
Exposure Duration (yr) 30
Body Weight (kg) 70
Exposed Skin Area (cm2) 2380
Adherence Factor (mg/cm2) 0.2
Absorption Rate (metals) (%) 0.1
Absorption Rate (organics) (%) 1
Exposure Time (hr/dy) 8
50
30
30
70
1960
0.2
0.1
1
24
Parameter
Resident
(Adult)
Resident
(Child)
Ingestion Rate (mg/event) 50
Exposure Frequency (dy/yr) 220
Exposure Duration (yr) 30
Body Weight (kg) 70
Exposed Skin Area (cm2) 2380
Adherence Factor (mg/cm2) 0.2
Absorption Rate (metals) (%) 0.1
Absorption Rate (organics) (%) 1
Exposure Time (hr/dy) 8
100
280
5
16
*2500
0.2
0.1
1
24"
24
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or chronic animal bioassays to which animal-to-human
extrapolation and uncertainty factors have been applied (e.g., to
account for the use of animal data to predict effects on humans).
The SFs for the carcinogenic contaminants of concern are
contained in Table 6-3.
As an interim procedure, until more definitive Agency guidance is
established, Region IV has adopted a toxicity equivalency
approach (TEF) methodology for evaluating carcinogenic PAHs.
This methodology is based on each compound's relative potency to
the potency of benzo(a)pyrene. The TEFs for the carcinogenic
PAHs are contained in Table 6-3.
Reference doses (RfDs) have been developed by EPA for indicating
the potential for adverse health effects from exposure to
contaminants of concern exhibiting noncarcinogenic effects.
RfDs, which are expressed in units of mg/kg-day, are estimates of
lifetime daily exposure levels for humans, including sensitive
individuals. Estimated intakes of contaminants of concern from
environmental media (e.g., the amount of.a contaminant of concern
ingested from contaminated drinking water) can be compared to the
RfD. RfDs are derived from human epidemiological studies or
animal studies to which uncertainty factors have been applied
(e.g., to account for the use of animal data to predict effectson
humans). The RfDs for the noncarcinogenic contaminants of
concern are contained in Table 6-3.
Lead exposure was evaluated using the Uptake/Biokinetic (UBK)
Model (version 4). This model can be used to predict blood lead
concentrations resulting from environmental concentrations of
lead. The Agency has adopted a blood lead benchmark of
10 micrograms per deciliter (10 ug/dl).
6.1.4 Risk Characterization
For carcinogens, risks are estimated as the incremental
probability of an individual developing cancer over a lifetime as
a result of exposure to the carcinogen. Excess lifetime cancer
risk is calculated from the following equation:
Risk = GDI x SF, where:
risk = a unit less probability of an individual developing
cancer;
GDI = chronic daily intake averaged over 70 years
(mg/kg-day); and
SF = slope factor, expressed as (mg/kg-day)"1.
These risks are probabilities that are generally expressed in
scientific notation (e.g. 1 x 10"6). Excess lifetime cancer risk
of 1 x 10"6 indicates that, as a reasonable maximum estimate,
25
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Table 6-3
Toxicity Values for Contaminants of Concern
Carcinogenic Slope Factors
Chemical
Benzo(a)pyrene3
Beryllimn
Dibenz(a,h)anthracene3
PCBs
Slope Factor
(mg/kg-dy)"1
5.8
4.J
5.8
7.7
Weight of
Evidence
Source
B2
B2
B2
B2
ECAO
IRIS
ECAO
IRIS
Reference Doses
Chemical
PCBs
Tetrac hloroethene
Lead5
Reference Dose
(mg/kg-dy)
1E-4
1E-2
Critical
Effect
Reproductive
Toxic ity
Hepatotoxicity
Source
ATSDR
IRIS
The toxicity equivalency factors (TEFs) used to evaluate
the carcinogenic PAHs are:
Compound
Benzo(a)anthracene
Benzo(b)fluoranthene
Benzo(k)fluoranthene
Chrysene
Dibenzo(a,h)anthracene
Ideno(1,2,3-c,d)pyrene
TEF
0,
0,
0.1
0.01
1.0
0.1
Lead exposure was evaluated using the Uptake Biokinetic
(UBK) model (0.4).
IRIS = Integrated Risk Management System *
ECAO = Environmental Criteria and Assessment Office
ATSDR = Agency for Toxic Substances and Disease Registry
26
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an individual has a 1 in 1,000,000 additional chance of
developing cancer as a result of site-related exposure to a
carcinogen over a 70 year lifetime under the specific exposure
conditions at a site. A summary of the potential current and
future risks are contained in Table 6-4.
For current use, estimated exposure pathway risks from
carcinogenic chemicals in site soils, sediments and surface water
are below the risk range of 1 x 10"4 to 1 x 10"6. The highest
exposure pathway risk is 6 x 10"7 for the ingestion of surface
soil by an on-site trespasser. The cumulative risk for the
current trespasser scenario is 1 x 10"6. The cumulative risks
for the future potential exposure pathways do not exceed the
protective risk range. The highest estimated future cumulative
risk (2 x 10'5) is for the future potential child resident. This
risk is due to the potential ingestion of PCBs in surface soil.
The potential for noncarcinogenic effects is evaluated by
comparing an exposure level over a specified time period
{e.g., lifetime) with a reference dose derived for a similar
exposure period. The ratio of exposure to toxicity is called a
hazard quotient (HQ). By adding the HQs for all contaminants of
concern that affects the same target organ (e.g., liver) within a
medium or across all media to which a given population may
reasonably be exposed, the hazard index (HI) can be generated.
The HQ is calculated as follows:
Noncancer HQ = CDI/RfD, where:
GDI = chronic daily intake;
RfD = reference dose;
and GDI and RfD are expressed in the same units and
represent the same exposure period (i.e., chronic,
subchronic, or short term).
A summary of the potential current and future HQs are contained
in Table 6-5. This table contains risk information for chemicals
and/or pathways which have individual or cumulative HQs of
greater than 0.1. The HQs for all current and future exposure
pathways are below 1.0.
The assessment of lead in blood for current and future exposure
indicates that 96% of exposed children would have blood lead
levels below the Agency benchmark of 10 ug/dl. This study uses
an average site lead concentration. There are individual areas
on-site with lead concentrations exceeding the surface soil
remediation goal. The cleanup goal for lead is protective of
children and groundwater. *
The level of confidence that one has in the information produced
by the risk characterization process is dependent on the validity
27
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Table 6-4
Summary of Site Risks
Current Risks (Trespasser)
Ingestion Ingestion
Chemical (Soil) (Sediment)
Benzo(a)pyrene 7E-8 NA
PCBs 5E-7 4E-7
Future Risks (Onsite Worker)
Ingestion Dermal Ingestion
Chemical (Soil) (Soil) (Sediment)
Benzo(a)pyrene 6E-7 NA NA
Beryllium 2E-7 NA NA
,Dibenz(a,h)anthracene 1E-7 NA NA
PCBs 4E-6 1E-6 2E-6
Future Risks (Child Resident)
Ingestion Dermal
Chemical (Soil) (Soil)
PCBs 2E-5 1E-6
Future Risks (Adult Resident)
Ingestion Inhalation
Chemical (Soil) (Air)
PCBs 2E-6 2E-6
Cumulative Risks
Scenario Risk Levela
Current Trespasser 1E-6
Future Worker 1E-5
Future Resident (Child) 2E-5
Future Resident (Adult) 6E-6
a The cumulative risks may be slightly higher for some
scenarios than the additive risks contained on this
summary page due to the contribution of low level risks
from other site contaminants.
NA Notation indicates that chemicals were carried through"
the risk assessment but did not produce risks at levels
of concern.
2 8
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Table 6-5
Summary of Hazard Quotients3
Future Risks (Onsite Worker)
Chemical Inhalation
PCBs 5E-2
Tetrachloroethene 6E-2
Cumulative 1E-1
Future Risks (Child Resident)
Chemical Ingestion (Soil)
PCBs, 4E-1
Leadb
Future Risks (Adult Resident)
Chemical Inhalation
PCBs 2E-1
Tetrachloroethene 3E-1
Cumulative 5E-1
The hazard quotients are summarized in this table for
which the cumulative hazard index is equal or greater
than 0.1.
The lead biokinetic model indicates that 96% of the
potential future exposed population will have blood lead
levels below the Agency benchmark of 10 ug/dl. This
prediction is based on the arithmetic average of lead
concentrations at the site. It should be noted that
there are individual areas of the site where lead
concentrations exceed the soil remediation goal.
29
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of the information used in the previous stages of the risk
assessment. Although uncertainties are inherent in all four
stages of a risk assessment, the most significant uncertainties
in,this assessment are probably associated with the toxicity
assessment for carcinogenic PAHs and the evaluation of the dermal
absorption exposure route.
Historically, the Agency has evaluated the carcinogenic PAHs by
summing and estimating the risk with the carcinogenic slope
factor for benzo(a)pyrene (BaP). The Agency recognizes that this
could be an overly conservative approach and is currently
evaluating the use of relative potency factors for assessing the
carcinogenic potency of these compounds relative to BaP.
Although there is some uncertainty with the relative potency
approach, Region IV EPA has decided to use this method because we
feel that it gives a better approximation of the risk associated
with this class of chemicals.
Another area of uncertainty is the evaluation of the dermal
absorption exposure route. There is not.a large database for the
dermal absorption of contaminants in soil. Consequently, there
is considerable uncertainty associated With the assumptions for
absorption and soil contact rate for dermal contact with soil and
sediment.
The Area-Wide Groundwater Risk Assessment did not address current
exposure since on-site groundwater is not currently being used.
However, the risks associated with possible future exposure for
workers or residents exceeds the risk range for both the shallow
and deeper Floridan Aquifer, the current source of municipal
water supplies in the area. For this reason, actual or
threatened releases of hazardous substances from the site soils
and sediments, if not addressed by implementing the response
action selected in this ROD, may present an imminent and
substantial endangerment to the public health, welfare, or the
environment. The endangerment is a result of the potential for
further degradation of the area-wide groundwater via leaching of
contaminants from the contaminated site soils and sediments.
6.2 Ash Pile Risk Assessment
6.2.1 Contaminants of Concern
Four discrete samples were collected from the ash pile and
analyzed for target analyte metals, target compound list
organics, total petroleum hydrocarbonds and toxicity
characteristic leaching procedure (TCLP). The analytical data
from the ash pile samples indicated that the only contaminant of
concern is lead. The average concentration of lead in
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6.2.2 Exposure Assessment
The potential pathways for exposure to the lead in the ash pile
are the same as those evaluated for the Site Source Risk
Assessment. The exposure scenarios evaluated in the Site Source
Risk Assessment were for a current trespasses, a future
industrial worker and a future on-site resident.
6.2.3 Toxicity Assessment
Currently, there are no Agency-verified toxicological values
(reference dose or cancer slope factor) for lead. Although lead
has been classified as a probable human carcinogen (Group B2),
EPA has not developed a cancer slope factor due to the
considerable uncertainty associated with the experimental data.
Also, lead does not appear to be a potent carcinogen and at low
levels, the non-cancer effects of lead are of greatest concern
for regulatory purposes.,
The noncarcinogenic health effects of lead are generally
correlated with level of lead in the blqpd. Lead is unique, in
that, it is difficult to identify a blood lead level or threshold
level below which there are no minimal health effects. Although
no threshold is apparent, risks of effects appear more likely at
blood lead levels of 10 to 15 ug/dl and higher. For this reason,
the Agency has adopted a blood lead benchmark of 10 ug/dl.
Elevated blood lead levels are associated with a broad range of
health effects. Some of these effects are interference with heme
synthesis necessary for formation of red blood cells, anemia,
kidney damage, impaired reproductive function, interference with
vitamin D metabolism, impaired cognitive performance (as measured
by IQ tests, performance in school, and other means), delayed
neurological and physical development and elevations in blood
pressure.
6.2.4 Risk Characterization
The Office of Solid Waste and Emergency Response (OSWER)
Directive #9355.4-02 entitled "Interim Guidance on Establishing
Soil Lead Cleanup Levels at SuperfundSites" recommended that
Superfund site soils for residential land use be remediated to
500 to 1000 mg/kg. This is based on the Centers for Disease
Control (CDC) statement that "... lead in soil and dust appears
to be responsible for blood levels in children increasing above
levels when the concentration in the soil or dust exceed 500 to
1000 ppm."
Since this directive, the Environmental Criteria and As«essment
Office of the Office of Research and Development (ECAO/ORD) has
developed the Uptake/Biokinetic (UBK) Model which provides a
method for predicting blood lead levels in populations exposed to
31
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lead in the air, diet, drinking water, indoor dust and soil. The
model focuses on infants and young children as the most sensitive
populations. OSWER recommends that this model should be used
with a blood lead cutoff concentration of 10 ug/dl with 95% of
the-children exhibiting blood leads below that level to determine
an acceptable maximum soil lead concentration.
A directive is currently being prepared by OSWER which will-
replace Directive #9355.4-02. This directive is recommending
that 500 ppm (based on application of the UBK Model) be used as a
preliminary remediation goal for lead in soil at CERCLA sites and
an action level at RCRA corrective action sites. This 500 ppm
value was derived to be protective of health for children (age 6
months to 7 years) by using national average values for lead
concentration in water and air, average age-specific dietary
intake rates and a bioavailability of lead from soils of 30%.
The average lead concentration in the ash pile (3525 ppm). not
only exceeds the recommended remediation goal of 500 ppm but also
exceeds the upper end of the range (1000 .ppm) specified in the
initial OSWER lead directive. In addition, the average lead
concentration also exceeds the groundwater protection
concentration of 284 ppm.
The UBK Model indicates that 500 ppm is the soil lead
concentration which is protective for children. Currently, there
is not an approved method for determining a soil lead level which
is protective of adults. Since infants and children are the most
vulnerable populations exposed to lead, it is generally felt that
a higher level of lead could be used for a remediation goal at
industrial sites. Until more information is available for
determining a risk-based soil lead remediation goal, Region IV
EPA recommends that the upper end of the OSWER range (1000 ppm)
be used for industrial sites. However at this site, the
groundwater protection concentration of 284 ppm is lower and
should be used as the remediation goal for the ash pile.
6.3 Environmental Risks
The environmental risks at this site are being addressed in a
separate study known as the Area-Wide Wetlands Impact Study.
This study evaluates the ecological status of the wetlands
associated with the Bay Drums, Peak Oil and Reeves Southeastern
Sites. The results of this study are contained in the Area-Wide
Wetlands Impact Study Report. The wetlands associated with these
three sites will be addressed in a separate operable unit ROD.
32
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7.0 Description of Remedial Alternatives
Soils and Sediments
The-Peak Oil Site Source Feasibility Study report presents the
results of a detailed analysis conducted on five potential source
remedial action alternatives for the Peak Oil Superfund Site.
These alternatives have been developed to address on-site soils
and sediments which may act as a source of chemical migration
into the groundwater, or may act as an exposure source at the
site. This section of the Record of Decision presents a summary
of each of the five alternatives that are described in the FS
report.
Alternative No. 1 - No Action
Alternative No. 2 - Containment
Alternative No. 3 - In-Situ Treatment
Alternative No. 4 - Ex-Situ Treatment
Alternative No. 5 - Off-Site Disposal
7.1 Alternative No. 1: No Action
Alternative No. 1 is divided into two subalternatives: strict no
action and limited action. A no action alternative is required
by the NCP to be carried through the detailed analysis to provide
a baseline for comparison of other alternatives.
7.1.1 Alternative No. 1A: No Action
In the No Action alternative, no further remedial action would be
taken at the Peak Oil Site. While EPA guidance allows the
inclusion of environmental monitoring in this alternative, no
measures may be taken to reduce the potential for exposure
through the use of institutional controls, containment,
treatment, or removal of contaminated soils or sediments. This
alternative does not meet the remedial action objectives for
preventing dermal contact or ingestion. As required by SARA, the
no* action alternative provides a baseline for comparison with
other alternatives that provide a greater level of response.
The primary applicable or relevant and appropriate requirement
(ARAR) for this alternative is the treatment technique action
level for contaminants in groundwater from the Safe Drinking
Water Act (SDWA). If no action is taken to treat or contain
contaminated site soils, contaminants may continue to leach into
the groundwater above the action levels. For this reason,
Alternative 1A does not meet ARARs.
There is no cost associated with the No Action alternative.
33
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7.1.2 Alternative No. IB: Limited Action
Alternative No. IB includes access restrictions and monitoring to
protect human health and the environment. Under this
alternative, no .source control remedial measures would be
undertaken at the Peak Oil Site. The major components of this
alternative include:
o Maintenance of existing chain-link fence with replacement of
warning signs around the site;
o Deed restrictions to prevent development and use of the
site;
o Annual inspection and maintenance of the site fence and
signs;
o Groundwater monitoring;
Access restrictions include the institution of deed restrictions,
maintenance of the existing fence, and replacement of warning
signs around the site. Deed restrictions would restrict future
on-site development which is not compatible with the protection
of human health and the environment. Warning signs would be
replaced.
Monitoring includes annual maintenance of the fence and warning
signs and groundwater monitoring. Annual maintenance is
necessary to ensure that the fence and warning signs for the site
are in good condition. Groundwater monitoring would be conducted
as addressed in the Area-Wide FS no action alternative to observe
any changes in contaminant levels and to assure protection of
human health and the environment.
Summary of Remedial Alternative Evaluation:
The Baseline RA indicates that the risks posed by exposure to
on-site soils for the scenarios evaluated are within the range
considered generally protective of human health. The limited
action alternative would not result in a reduction in risk from
exposure to site soils.
In this alternative, certain chemicals present in the source area
soils would continue to desorb into the groundwater system. The
resultant concentrations in the groundwater system may exceed
health- or environmental-based criteria. Therefore, protection
of human health and the environment is not achieved by this
alternative, and degradation of the surficial aquifer would
continue. «•
Regarding long-term effectiveness and permanence of this
alternative, the deed restrictions (restricting future on-site
34
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development) and maintenance of the fence and signs minimize
health risks within the protective range. The reliability of
this alternative is dependent on future implementation of the
control measures. Five-year reviews of the site would be
conducted to determine the need for additional remedial action.
This alternative would not reduce the toxicity, mobility, or
volume of the impacted source soils. The volume of impacted soil
may increase due to chemical constituent migration, and the
toxicity may slowly decrease over time due to dilution and
volatilization.
Implementation of this alternative would not result in additional
short-term risk to the community or the environment.
The filing of deed restrictions is administratively feasible and
would require the cooperation of the owner of record of the site.
The annual fence and warning sign inspection and maintenance
program would be easily implemented.
The estimated costs associated with this alternative are
presented in Table 7-1. Assuming that the alternative is
implemented for a 30-year period, the present-worth cost of this
alternative is estimated to be $123,000.
7.2 Alternative No. 2: Containment
The primary objective of this alternative is to eliminate the
mobility and exposure pathways of site chemicals by containment.
Containment is achieved by the installation of a slurry wall
around the site, placement of a multimedia cap over the area, and
dewatering the surficial soils within the slurry wall. The major
components of this alternative include:
o Demolition of site buildings, fence, and railroad tracks,
where necessary, to construct the slurry wall and site cap;
t
o Construction of a slurry wall around the impacted site
soils;
o Grading of the site in preparation of cap placement;
o Placement of a multimedia cap with perimeter drains to
channel surface water runoff to the ditch south of Reeves
Southeastern Wire and to the ditch north of the Peak Oil
Site;
o Installation of monitoring wells in areas both within and
outside the slurry wall; «•
o Installation of extraction wells to dewater surficial soils
within the slurry wall as addressed in the Area-Wide FS;
35
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TABLE 7-1
COST SUMMARY OF REMEDIAL ALTERNATIVES
PEAK OIL SUPERFUND SITE
TAMPA. FLORIDA
'•ehnoloev
CAPITAL COSTS (DIRECT)
Ground Water Monitoring Wefle
Muromedia Cap
Sol Cover
Slurry W«0
Orversion/CoBection
Revae*tation
Vapor/Duet Suppraaion
jccavation
Sheet Pile
Dewetering Sump*
In-Situ Treatment
In-Situ Stabilization
Sol Wething
StabKzation 10.000 ton.
OTf-Siu Dnpoaal 1.300 ey
A--«l.« •—J--efn»ntffl**fiB
SUBTOTAL
CAPITAL COST* (mOMeCT)
12
6.00CTW
6D«onM
40.000 «f
6^ocre*
46.0000V
14,600 «f
6
2.600 ey
69.OOOtor»
69XMO tom
69.000 ton*
44.700 ey
46 OOO ev
Engineering. Legal. Adminiatrativa (16%) W
r ' M/WI
SUBTOTAL
OPERATION AND MAMTENANCE
COSTS (ANNUAL)
Treatment Syatem O&M and Periodic She Vieita
Year 1 through 6
Yoir 6 through 30 .
RexUw Every five Yoora
SUtTOTAL (O4M PRESENT WORTH)
TOTAL PRESENT WORTH (hi
R.m«diel AlLmeovet
1A
Limited C
Action
(e)
-
-
-
«.
-
-
_
-
-
_
-
-
^
-
_
O
10.000
10.000'
20.000
1.000
1^00
60.000
103^00
•123^00
2
ontBiflflMnt
1«,000
7*4.000
-
366.000
_
-
—
— •
•-
-
_
-
-
—
-
_
1.170.000
176,000
234.000
410.000
1.000
1.000
60.000
1O3.0OO
,1.«3^00
3
In-Sru
Treatment
(e)
7*4.000
-
36*.000
w
22.000
.-
..' _
-
-
620.000
276.000
-
^
„
-
^
2469,000
310,000
414,000
724.000
79X>00
1,000
60.000
421.000
•3.221.000
4A 48
Ez-ehu Treatment
Soil
Waahing
fe)
-
126.000
369.000
26.000
22.000
102.000
•10.000
167.OOO
64^00
_
-
«,329',000
^
166^00
-
336.000
10^95,000
1.644.000
2.059.OOO
3.603.000
1400
1400
^
1040O
•13,90*400
Thermal
Oeeorption
(e)
-
126.000
36*400
26400
22400
102.000
610400
167.000
64.000
-
-
-
16.300.000
690400
-
.420. OOO
17'**S400
2.6*3400
3.S77.OOO
6.260.000
•1400
1400
^
10400
•24.185400
5
Off-Sit*
Oitpoeal
(c)
-
-
368.000
_
22.000
102.000
610.000
167.000
64400
-
-
-
—
^
94400.000
480.000
96.0*3.000
4.WO.OOO
19.220.000
24.020.000
-
-
f
•
•120.103.000
U) foe eff-«ru tfi»pOMl. «v» »oo«it to
for
Ugd. and •dmintotr
For no •etfen. lump Mm§ «r* UMd.
ft! Olf-«it« tape** co«t Mwm** •! (08 wiB hew to b* IneiiMrctcd to comply with Und dupOMl traMnMnt rwttiction eundwd*.
(c) iMm on coctod in th« ArM-Wid« FS. «.
36
-------
o Construction of a chain-link fence and placement of warning
signs around the perimeter of the slurry wall;
o Deed restrictions to prevent subsurface development and
- limit use of the site;
o Annual inspection, maintenance, and report of the cap,•
fence, and signs, and monitoring of water levels inside and
outside the slurry wall;
o Groundwater monitoring;
o v Five-year reviews of the site to evaluate the necessity of
additional remedial actions.
Site preparation would be required to implement the main
components of this alternative. Site preparation includes
construction of adequate access roads to the site for
construction vehicles and equipment delivery, installation of
project offices and decontamination facilities, and demolition of
existing site structures. Existing site structures include the
following: two buildings located in the northwest corner of the
site, two smaller buildings located in the central area of the
site, and a concrete pad located in the southeast portion of the
site.
A slurry wall would be constructed at the Peak Oil Site to
contain impacted soil and to dewater the area within the slurry
wall. Sections of the slurry wall may need to be constructed on
adjacent properties. This is necessary for slurry wall
installation in areas without contamination. Approval would have
to be obtained from adjacent property owners in the form of
easement agreements, leases, or outright purchases of adjacent
properties. Construction of a slurry wall is detailed on
Figure 7.1. The slurry wall would have a perimeter of
approximately 2,000 feet and enclose an area of about six acres.
The slurry wall will be composed of a clay material and will be
keyed into the Hawthorn Formation at an average depth of 20 feet.
For this scenario, a multimedia cap would be constructed to cover
the entire area enclosed by the slurry wall. Grading of the site
would be conducted prior to placement of the cap. As shown on
Figure 7.2, a two-foot compacted clay layer would be placed over
the impacted soils. This soil cover would be compacted in six-
inch lifts. A 60-mil synthetic liner would be placed over the
clay layer. A one-foot sand layer would be placed above the
liner to provide drainage. The top foot of cap would consist of
topsoil to provide a root zone for vegetative growth. In order
to prevent clogging of the sand drainage layer, a filter fabric
would be placed between the topsoil and sand layer.
37
-------
TRENCH
X
BACKHOE
FINAL LEVEL OF BACKFILL
OJ
00
PLAN VIEW
BACKHOE
EXISTING GROUND
SURFACE
SURF1CIAL AQUIFER
(SAND)
,,BACKFlLLf,'/,7,
UPPER FLORIDAN AQUIFER
(UMEROCK)
PRQFIL
MILES;
1. SLURRY WALL IS KEYED
INTO THE LOW PERMEABILITY
LAYER.
PLAN AND PROFILE OF
SLURRY WALL CONSTRUCTION
PEAK OIL SUPERFUND SITE
TAMPA, FLORIDA
FIGURE 7.1
-------
GROUND SURFACE-
2% MINIMUM SLOPE
FILTER FABRIC
60 mil SYNTHETIC LINER
S4M?
CLAY
IMPACTED SOIL
TYPICAL
MULTIMEDIA CAP
PEAK OIL SUPERFUND SITE
TAMPA. FLORIDA
FIGURE 7.2 *
39
-------
The topsoil would be vegetated to prevent erosion. The cap would
have a minimum slope of two percent. Surface runoff would be
controlled by drainage channels which direct runoff to the ditch
south of Reeves SEW and the ditch north of the Peak Oil Site.
Precipitation that percolates through the topsoil would flow
laterally through the sand drainage layer and into the drainage
channels. Ten extraction wells would be installed, as addressed
in the Area-Wide FS, within the slurry wall to dewater the
surficial soils and to ensure an inward hydraulic gradient is
maintained. A pipe network would be installed to transfer
extracted groundwater to a system proposed in the Area-Wide FS
containment alternative for treatment. An oil/water separator
would be installed (if necessary) for pretreatment of Peak Oil
extracted groundwater.
This containment alternative also includes monitoring and access
restrictions. Groundwater monitoring would be conducted within
and outside the slurry wall to verify that the slurry wall is
preventing contaminant migration and maintaining hydraulic
control. Six monitoring well pairs would.be installed to achieve
this objective. Well sampling would be .conducted semiannually
the first three years and annually thereafter. A 30-year time
period is used for comparative analysis. In addition,
groundwater monitoring would be conducted as proposed in the
Area-Wide Groundwater FS to verify chemicals of concern are not
migrating off-site. Access restrictions include five-year
reviews and deed restrictions. Construction of a new fence would
be required around the slurry wall with appropriate warning
signs.
Summary of Remedial Alternative Evaluation:
Construction of the slurry wall, regrading of the site, and
installation of the multimedia cap would prevent degradation of
the surficial aquifer system. The piezometric surface within the
slurry wall would be lowered by dewatering, producing a net
inward hydraulic gradient into the site area. By elimination of
surface water infiltration and creating a net inward hydraulic
gradient, degradation of the surficial aquifer system beyond the
slurry wall would be eliminated. In addition, the potential for
direct exposure to chemical constituents in on-site soils would
be eliminated by the placement of a cap.
The multimedia cap would be constructed in a manner which
complies with action-specific ARARs. The cap construction and
site regrading would not impact the nearby wetlands. However,
this alternative may not comply with groundwater ARARs because
groundwater standards would not be achieved for the residual
groundwater in the dewatered containment area. *
Annual maintenance of the multimedia cap, fence, and signs;
continual maintenance and monitoring of the piezometric
40
-------
differential within the slurry wall; monitoring of groundwater
quality across the slurry wall; and continued implementation of
deed restrictions which restrict future on-site development at
the site, are all required to assure the .long-term effectiveness,
integrity, and permanence of this remedial action. The overall
long-term effectiveness of this alternative would be determined
by five-year reviews of the site which would evaluate the need
for additional remedial action.
This alternative eliminates migration of constituents from the
site area and thus reduces the mobility of site chemicals. The
toxicity and volume of the impacted source soil would remain
essentially unchanged, however chemicals of concern which have
desorbed from the soil into the groundwater would be removed by
dewatering the site.
This alternative may result in short-term increase in exposure
potential to the community and on-site workers. Construction of
the slurry wall and cap may cause volatilization of organics or
emission of impacted dust, thus resulting.in temporary impacts to
the ambient air quality.
The estimated construction time required to complete the remedial
action portion of this alternative is 12 weeks.
The implementation of this alternative is directly influenced by
the attainment of deed restrictions for the site and for
easements and agreements for portions of property adjacent to the
site where the cap would be constructed. The area over which the
multimedia cap would be constructed includes both on- and off-
site areas. Additionally, structures and railroad tracks would
have to be removed.
This alternative utilizes proven and reliable construction
methods which are readily implemented. Services for this
alternative are readily available. The multimedia cap would be
constructed using imported material which is also available.
Therefore this alternative is technically implementable.
The cost estimate for this alternative is presented in Table 7-1.
The estimated present-worth cost of this alternative is
$1,683,000.
7.3 Alternative No. 3: Zn-Situ Treatment
This alternative includes in-situ treatment technologies to
reduce mobility, toxicity, and volume of contaminants at the Peak
Oil Site. In-situ treatment provides an alternative to ex-situ
technologies which may cause short-term increases in contaminant
exposure during excavation and treatment of impacted soils.
In-situ technologies considered for this site include
bioremediation, soil flushing, vacuum extraction/soil aeration,
41
-------
and stabilization. Effectiveness of in-situ methods, in most
cases, must be determined on a site-specific basis using
laboratory and pilot-scale treatability studies. For the purpose
of conducting a detailed analysis, this alternative includes
bioremediation and soil flushing as the primary in-situ process
technologies. Vacuum extraction/soil aeration could be added
during remedial design if it is determined that this process
option is more effective at removing VOCs, which are found
primarily in the northern section of the site. In addition,
lead-impacted soil with concentrations above the soil remediation
goal of 284 ppm (see Table 9-1) will be solidified/stabilized.
The in-situ treatment alternative includes the site preparation,
slurry wall construction, and multimedia cap construction
components identified in Alternative No. 2. The major components
of this alternative include:
o Demolition of buildings, fence, and railroad tracks, where
necessary, to construct the slurry wall;
o Construction of a slurry wall around,the impacted site soils
(see Figure 7.1) ;
V • . " '
o Construction of a chain-link fence and placement of warning
signs around the perimeter of the site;
o Excavation and solidification/stabilization of lead-impacted
soil with concentrations above the remediation goal of
284 ppm;
o On-site disposal of solidified/stabilized soil;
o Installation of a groundwater recovery system which includes
extraction wells and collection header piping;
o Installation of a mixing system to add necessary nutrients
and dissolved oxygen (or hydrogen peroxide) to the
groundwater for infiltration;
o Installation of a delivery system (leach field piping or
spray irrigation) to provide infiltration of treated
groundwater;
o Implement weekly maintenance and operation of in-situ
v treatment system;
o Implement periodic monitoring to optimize the hydrodynamics
of the extraction wells and infiltration field, track the
effectiveness of the biodegradation and soil flushing
processes, and maintain the levels of nutrients and oxygen
in the media at proper levels to ensure biodegradation;
42
-------
o Install cap as discussed in the containment alternative
after in-situ treatment is completed;
o Groundwater monitoring;
o Conduct five-year reviews after treatment is completed to
evaluate the necessity of additional remedial actions.. •
Following site preparation and construction of the slurry wall
for hydrogeologic control, a fence would be installed with
appropriate warning signs.
Excavation and solidification/stabilization of lead-impacted soil
with concentrations above the remediation goal of 284 mg/kg.
Treatability studies shall be conducted to determine whether the
lead-impacted soils will be solidified prior to the in-situ
treatment of organic-contaminated soils. This is necessary due
to the lead-impacted areas also being impacted with organic
substances which may hinder the ability to meet solidification
performance standards. If treatability studies illustrate that
performance standards cannot be met, the solidification phase of
remediation will occur after completion of the soil flushing/
bioremediation phase (treatment of organics).
Groundwater recovery and recharge systems would be installed to:
1) provide adequate contact between treatment agents and impacted
soils and 2) provide for complete recovery of surficial aquifer
groundwater within the slurry wall.
A groundwater extraction scenario consisting of wells would be
used to recover groundwater as shown on Figures 7.3 and 7.4. The
surficial aquifer would be initially dewatered to approximately
one to three feet above the low-permeability unit. This allows
flushing of surficial sands and distribution of oxygen and
nutrients to stimulate biodegradation. After initial dewatering,
a steady-state groundwater recovery rate of 20 gpm was estimated,
accounting for recharge which would result in flushing the
aquifer within the slurry wall approximately two times per year.
The recovered groundwater would be transferred to a groundwater
treatment system for heavy metals and treatment of organic
compounds. Pretreatment may be required to remove certain
substances (such as oil) that would not be compatible with a
treatment system identified in the Area-Wide ROD. Integration
with the Area-Wide ROD is required with this alternative because
it combines in-situ soil treatment (soil flushing and
bioremediation) with groundwater treatment. A treatability study
would be required in the design phase to determine if surfactants
can be used to enhance the soil flushing process. *
A surface gravity delivery system which involves application of
water for flushing directly to the surface is proposed for this
43
-------
TO GROUND WATER ^_ -^ 6" -8" THICK -\ __
TREATMENT SYSTEM \ o..^,^^ \ L^* OF PEA \ ^\
(TYPICAL) \ GRAVEL \
"%Tj^<9 o^^f^T
\ ; f i
GROUND WATER — s.
EXTRACTION WELL \
(TYPICAL) • >
GROUND WATER -i
DRAWDOWN
V
\
-
~~
f__
w*
i i. i
SURFJCIAL AQUIFER
(SAND}
.
7
/^ ~~^
/ \
__
\
gg^TjFt. ov o^^S*
j i\ i
\
\
PERFORATED PIPE FOR -^
RECHARGE OF TREATED
GROUND WATER (TYPICAL)
7
/ \
__
__
^^A*^^ ®"^^
i
ID
/ .1
CM
i
0
.
o
CN
1
tfl
_2
' i
'/ LOW PERMEABILITY
LAYER (CLAY}
NOTES:
1. REFER TO DWG. 87-438-M78
FOR PROPOSED IN-SITU TREATMENT
SYSTEM PLAN.
TYPICAL PROFILE OF PROPOSED
IN-SITU TRF^TMENT SYSTEM
PEAK OIL SUPERFUND SITE
TAMPA, FLORIDA
FIGURE 7.3
-------
_..!-! .-CATE'
• - ' ' •«*••*• f
.
* r _ * --^ • •*" S~-"-~ * * • ir^
..-TANKS
LEGEND:
~:m UWUPROVEO ROADWAY
x- — — DRAMACE OUCH
-— DIRECTION or suRr*ct WATER rio»
CD STANDING WATER
rt"^.< tOCt Of WOODED ARtA
op*
. HARSH
PROPOSED SlURRY WAIL
.1
PROPOSED GROUND WATER EXTRACTION WEll
mm PROPOSED GROUND WAICR RECHARGE
NETWORK
PROPOSED GROUND WATER EITRACTION
NETWORK
.NQIES;
COORDINATE GRID IS REFERENCED 10
THE FLORIDA STATE PLANE COORDINATE
SYSTEM.
REFER TO DWG. «7-«J«-A77 TOR TYPICAL
PROHIC Or PROPOSED IN-SHU TREATMENT
SYSTEM.
PROPOSED IN-SITU TREATMENT SYSTEM
PLAN
SITE SOURCE CHARACTERIZATION
PEAK OIL SUPERFUND SITE
TAMPA. FLORIDA
FIGURE 7.4
-------
alternative. This system consists of distribution piping or
spray irrigation as shown on Figure 7.3 which would provide
adequate coverage of the site area. Due to the permeable nature
of the site soils, a gravity surface delivery system would
effectively allow percolation of water through the dewatered
aquifer to the extraction zone.
In this scenario, treated groundwater from the groundwater
treatment system would be transferred back to the Peak Oil Site
for infiltration. Prior to recharge, mixing systems would be
utilized to add nutrients (such as nitrogen and phosphorus) and
oxygen to support microbial activity for biodegradation. Optimum
nutrient mix can be determined by treatability studies.
Biodegradation is dependent upon oxygen availability, and
sufficient oxygen levels can be maintained by injecting hydrogen
peroxide into the groundwater.
For this scenario the in-situ treatment period is estimated to be
fiye years. After completion of the treatment period a
multimedia cap would be placed over the site. The in-situ
treatment alternative would require implementation with an Area-
Wide groundwater alternative that would adequately treat the
groundwater for surface recharge back into the surficial aquifer.
Summary of Remedial Alternative Evaluation:
This alternative would result in a reduction of organic and
inorganic chemical concentrations in the Peak Oil Site source
soils by in-situ treatment. Protection of groundwater by this
alternative is provided by treatment of source soils,
construction of a slurry wall, removal and treatment of the
groundwater, and placement of a multimedia cap after completion
of in-situ treatment. Environmental risks outlined in the
Baseline RA are also reduced.
This alternative is expected to comply with chemical-, location-,
and action-specific ARARs. Achievement of chemical-specific
ARARs can only be assessed by performing treatability studies.
Because source soils are flushed and bioremediated or stabilized
during the in-situ treatment period, leachable contaminants,
which may contribute to noncompliance with groundwater ARARs, may
be*reduced or eliminated. Impacted groundwater generated from
this alternative would be treated in a groundwater treatment
system to meet ARARs for groundwater recharge.
The long-term effectiveness of this alternative is provided by
stabilization or biodegradation and flushing of leachable organic
and inorganic compounds in site source soils. Placement of the
multimedia cap after treatment would substantially reduce any
exposure risks due to constituents not effectively removed by the
46
-------
in-situ treatment process. Five-year reviews of the site would
be conducted to assure protection of human health and the
environment.
The-toxicity, mobility, and volume of the site hazards would be
reduced by this alternative. Treatability studies would have to
be conducted to determine the effectiveness of in-situ methods in
reducing or removing site contaminants. In-situ treatment is
proposed for five years, which would allow the surficial aquifer
sands to be flushed approximately 10 times, two cycles per year.
Chemicals flushed into the groundwater from surficial sands are
removed by the groundwater treatment system. After completion of
the treatment period, verification sampling would be required to
confirm the level of contaminant reduction.
The in-situ alternative requires minimal excavation of
contaminated soils, which provides short-term effectiveness by
reducing exposures to on-site workers and/or the community during
the remedial action period. The in-situ .alternative would
require an extended treatment period of approximately five years.
Because implementation of this alternative would not increase
short-term exposures or risks at the site, a longer treatment
period would still provide adequate short-term effectiveness.
The implementation of this alternative is directly influenced by
the attainment of deed restrictions for the site and easement
agreements for portions of properties adjacent to the site, in
order for the construction activities to be completed.
V
This alternative involves use of several standard construction
techniques, including construction of the multimedia cap and
slurry wall. Also, in-situ technology services are readily
available.
The cost to implement this alternative is presented in Table 7-1.
As shown, the present-worth cost of this alternative is estimated
to be $3,221,000. This cost is based on a treatment period of
five years.
7.4 Alternative No. 4: Ex-Situ Treatment
This alternative includes ex-situ treatment technologies to
reduce mobility, toxicity, and volume of contaminants at the Peak
Oil Site. Ex-situ technologies considered for this site include
soil washing, high- and low-temperature thermal desorption,
bioremediation (bioreactor), and stabilization. The most
appropriate treatment option or combination of ex-situ process
technologies for the Peak Oil Site may be determined in«-the
remedial design stage after treatability studies have been
completed. For the purpose of conducting detailed analysis in
this FS, two ex-situ alternatives will be analyzed which include
47
-------
soil washing and high-temperature thermal desorption as the
primary ex-situ treatment technologies. Soil washing shall be
designated as ex-situ treatment Alternative No. 4A and high-
temperature thermal desorption as ex-situ treatment Alternative
No. -4B. The ex-situ soil remedial alternatives presented in this
section will require integration with the groundwater remedial
alternatives presented in the Area-Wide FS. Proposed Area-Wide
alternatives for groundwater include no action, containment, and
four active restoration alternatives.
7.4.1 Alternative No. 4A: Soil Washing
This alternative requires the excavation and treatment of site
source soils with soil washing as the primary technology to
reduce mobility, toxicity, and volume of contaminants at the Peak
Oil Site. The soil washing alternative includes the same site
preparation, access restrictions, monitoring requirements, and
slurry wall construction components as identified in Alternative
No. 2. The major components of this alternative include:
*
o Demolition of buildings, fence, and railroad tracks which
hinder construction of the slurry wall or excavation of
soils;
o Installation of a slurry wall around the soils impacted
above the established cleanup concentrations to control
groundwater during excavation;
o Installation of dewatering sumps for dewatering site soils
to the depth of excavation. Groundwater removed during
dewatering would be treated by a groundwater treatment
system;
o Construction of a fence around the slurry wall and placement
of signs on the fence;
o Excavation of site soils requiring remediation;
o Air quality monitoring at the site perimeter during
excavation activities;
o k Excavation of impacted soil and treatment by soil washing;
o Stabilization of silt/clay fines impacted by inorganic
constituents;
o Backfill of excavation with treated soil and grading of
filled area;
*•
o Regrade site and place soil cover to facilitate
revegetation;
48
-------
Replacement of site fence signs;
Annual inspection and maintenance of cap;
-o - Groundwater monitoring.
Following site preparation and construction of the slurry wall
-for dewatering, six dewatering sumps would be installed within
the slurry wall to dewater the site for soil excavation. A water
collection system would also be installed to transport the water
to the designated groundwater treatment system which would be
identified in the Area-Wide FS. A groundwater treatment system
would have to be installed and operational before dewatering is
initiated to treat extracted groundwater for discharge.
During dewatering, the soil washing treatment system would be
mobilized for installation on the Peak Oil Site. The soil
washing treatment system would require a construction and.
operation area of approximately 100 feet by 150 feet. To provide
this area, preliminary soil excavation of .contaminated surface
soils may be required on the northern part of the site and
stockpiled for future treatment. Clean backfill can be used for
preliminary surface excavations to provide an adequate treatment
area.
After initial dewatering and installation of the soil washing
treatment system, open pit excavation and limited sheet pile
?xcavation would be used to remove the source soil. Sheet pile
excavation would be required for excavations that are
sufficiently close to the slurry wall which could jeopardize its
structural integrity. Dust and vapor suppressants may be
utilized during excavation.
V
Soil washing would be used to initially treat the soils and
separate the large-grained sands from the fine-grained silts and
clays. Figure 7.5 shows the process diagram for soil washing.
Because a significant fraction of the chemicals in a soil matrix
tend to adsorb onto the silt, clay, or organic carbon portion of
soil, the removal of these finer soil fractions by use of soil
washing produces large-grained soils that can be backfilled into
the excavation without stabilization or further treatment. Also
produced are finer-grained soils which require treatment or
stabilization. Water used in the treatment process would require
further treatment for recycle or discharge.
Based on an estimated 46,000 cubic yards of impacted soil, 39,000
cubic yards of sands would provide clean backfill and 7,000 cubic
yards of fines (approximately 15 percent of the surficial sands)
would require further treatment or stabilization. This*includes
approximately 400 cubic yards of impacted soil which is located
49
-------
START
CONTAMINATED SOIL
SCRUBBER
SEPARATION OF
SAND AND
SILT/CLAY
SAND
WASH WATER
in
O
__ WATER
/Z$?:\ TO RECYCLE — TREATMENT
rWvWWX SYSTEM
CLEAN SAND 1
TO BACKFILL 1
DISCHARGE EXCESS
WATER
SILT/CLAY
FRESH WATER-
WASH WATER
SEPARATION OF
OIL FROM
WATER/SILT/CLAY
1
MULTIPLE-STAGE
SILT/CLAY
WASH
SILT/CLAY '
DEWATERING .
RECOVERABLE HYDROCARBONS
1
1 ) |r-«
TO OFF- SITE RECYCLE
CONTAMINATED SILT/CLAY
TO STABILIZATION PROCESS
SOIL WASHING SYSTEM
PEAK OIL SUPERFUND SITE
TAMPA, FLORIDA
FIGURE 7.5
-------
outside of the slurry wall. Excavations outside of the slurry
wall would be backfilled with clean fill. Typical soil washing
rates are about 5 to 20 tons per hour.
The-soil fines would be stabilized after soil washing.
Stabilization of the fines would prevent leaching of inorganic or
organic chemical residues remaining in the fines. The
stabilization process is shown on Figure 7.6. After
stabilization of the soil fines, the stabilized material would be
backfilled into the excavation and compacted. As a final
measure, the site would be regraded and a soil cover would be
applied to facilitate revegetation.
V
Summary of Remedial Alternative Evaluation;
This alternative would result in a permanent reduction of
inorganic and organic chemicals. Residual fines resulting from
the soil washing process would be stabilized. Protection, of
groundwater by this alternative is provided by soil washing,
stabilization of fines, and by the slurry ..wall. Risks outlined
in the Baseline RA are also substantially reduced.
This alternative would comply with all chemical-, location-, and
action-specific ARARs. Because soil is treated and stabilized,
this alternative would reduce or eliminate leaching of chemicals
from source soils which may contribute to noncompliance with
groundwater ARARs. Also, this alternative would meet applicable
landfill disposal requirements and would meet RCRA Land Disposal
Restrictions (LDRs). Soil which would be backfilled into the
excavation after treatment and stabilization would comply with
land disposal restrictions, and wastewater from the soil washing
operation would meet appropriate ARARs for process wastewater
discharge.
The long-term effectiveness of this alternative is assured by the
removal of inorganic and organic compounds and stabilization of
the residual fines. Continued implementation of the deed
restrictions are required to restrict development of the site
which is not compatible with protection of human health and the
environment.
The toxicity, mobility, and volume of the site hazards would be
substantially reduced by this alternative. However, a
treatability study must be conducted to determine the achievable
cleanup levels. Approximately 46,000 cubic yards of soil would
be processed by soil washing and about 7,000 cubic yards of fines
would be stabilized. The 7,000 cubic yards of fines for
stabilization would bulk about 30 percent to produce 9,000 cubic
yards of stabilized material for backfill into the excavation.
Wastewater sludge produced by the soil washing process is
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MATERIALS
FEED HOPPER
BACKFILL OF
STABILIZED MATERIAL
STABILIZATION PROCESS
PEAK OIL SUPERFUND SITE
TAMPA. FLORIDA
FIGURE 7.6
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included in this volume. Spent activated carbon may be produced
during implementation of this alternative and would require
regeneration at an appropriate facility.
Regarding the short-term effectiveness of this alternative, the
community and/or workers around and on the Peak Oil Site may
potentially be exposed to low levels of some metals or organics
due to dust emissions or volatilization during excavation of
soils. Dust or vapor suppressants would be used to reduce
emissions. This alternative also includes air quality monitoring
at*the site perimeter to assess potential air impacts. Worker
protection may be required for dermal contact and inhalation of
dust.
The estimated time required to complete the remedial action
portion of this alternative is 60 weeks.
The implementation of this alternative is directly influenced by
the attainment of easements or access agreements and deed
restrictions for the site and portions of property adjacent to
the site in order for excavation and construction activities to
be completed.
This alternative involves use of several standard construction
techniques including construction of the cap and slurry wall.
Although the soil washing technology is less common than the cap
or slurry wall, services are readily available. The footprint
size of the soil washing system is about 100 feet by 150 feet,
and a treatability study is required.
The cost to implement this alternative is presented in Table 7-1.
As shown, the present-worth cost of this alternative is estimated
tov be $13,908,000. This cost is based on excavation and
treatment of 46,000 cubic yards of soil.
7.4.2 Alternative No. 4B: High-Temperature Thermal Desorption
This alternative includes treatment of impacted soil by high-
temperature thermal desorption (HTTD). Alternative No. 4
contains the same site preparation, access restrictions,'
monitoring requirements, and slurry wall construction components
as identified in Alternative No. 2. Additionally, this
alternative includes the site fence and signs, dewatering and
soil excavation activities as are described in Alternative No.
4A. The major components of this alternative include:
o Demolition of buildings, fence, and railroad tracks which
hinder construction of the slurry wall or excavation of
soils; *
53
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o * Installation of a slurry wall around the soils impacted
above the established cleanup concentrations to control
groundwater during excavation;
o - Installation of dewatering sumps for dewatering site soils
to the depth of excavation. Groundwater removed during
dewatering would be treated by a groundwater treatment•
system;
o Construction of a fence around the slurry wall and placement
of signs on the fence;
o Excavation of site soils requiring remediation;
o Air quality monitoring at the site perimeter during
excavation activities;
o Excavation of impacted soil and treatment by high- .
temperature thermal desorption;
o Stabilization of soil impacted by inorganic constituents;
o v Backfill of excavation with treated soil and grading of
filled area;
o Regrade site and place soil cover to facilitate
revegetation;
o Replacement of site fence signs;
o Annual inspection and maintenance of soil cover;
o Groundwater monitoring.
Mobilization of the HTTD treatment system would occur during the
dewatering process and after site preparation and slurry wall
construction have been completed. The HTTD treatment system
requires a footprint of approximately 150 by 150 feet for a total
of 22,500 square feet. To provide this footprint, preliminary
soil excavation of contaminated surface soils may be required on
the northern part of the site and stockpiled for future
treatment. Clean backfill can be used to fill preliminary
surface excavations to provide an adequate treatment area.
Thermal desorption is a process that uses heat to vaporize
organic contaminants from soil. Figure 7.7 is a general process
diagram for a typical thermal desorption process. HTTD is not an
incineration process because destruction of organic compounds is
not the desired result. HTTD is a physical separation process
which would volatilize organic contaminants from soil, but would
not oxidize or destroy them. Contaminated soil is generally
heated between 800 and 1,200°F (optimum process temperature
54
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ui
ui
CLEAN SOLIDS
FOR BACKFILL
n
n
THERMAL
DESORBER
LI
U
CLEAN
OFF-GAS
WATER FOR RECYCLE
OR DISCHARGE
HYDROCARBON PRODUCT
FOR RECYCLE/DISPOSAL
THERMAL DESORPTION
PEAK OIL SUPERFUND SITE
TAMPA, FLORIDA
FIGURE 7.7
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determined based on treatability study) in the thermal desorption
unit, driving off water and volatile compounds. Off-gases may be
burned in an afterburner, condensed to reduce volume, or captured
by'carbon beds. Organic volatile compounds which can be
condensed, produce a hydrocarbon product stream which can be sent
off-site for recycle or incineration. Processing rates for the
HTTD process are in the range of 3 to 25 tons/hr.
In this alternative, approximately 46,000 cubic yards would be
excavated and processed by the HTTD process. This includes
approximately 400 cubic yards of impacted soil which is located
outside of the slurry wall. Excavations outside of the slurry
wall would be backfilled with clean fill. Thermally treated soil
would require stabilization for inorganic contaminants exceeding
cleanup levels. Figure 7.6 shows a typical stabilization
process. Stabilized soil would be backfilled in existing
excavations. The site would then be regraded and a soil cover
would be applied to facilitate revegetation.
Summary of Remedial Alternative Evaluation:
This alternative would result in a permanent reduction in the
organic chemicals and stabilization of inorganics in the soils.
Protection of groundwater by this alternative is provided by
thermal treatment, soil stabilization measures and by the slurry
wall. Risks outlined in the Baseline RA are also substantially
reduced.
This alternative would comply with all chemical-, location-, and
action-specific ARARs. Because soil is treated and stabilized,
this alternative would reduce or eliminate leaching of
contaminants from source soils which may contribute to
noncompliance with groundwater ARARs. Also, this alternative
would meet applicable landfill design and disposal requirements,
and would meet closure requirements. Soil which would be
backfilled into the excavation after treatment and stabilization
would comply with LDRs, and wastewater from the thermal treatment
operation would meet appropriate ARARs for process wastewater
discharge. Air emissions would meet appropriate federal and
state standards.
The long-term effectiveness of this alternative is assured by the
removal of organic compounds and stabilization of inorganic
constituents. Organic removal and inorganic stabilization are
permanent. Continued implementation of the deed restrictions are
required to restrict development of the site which is not
compatible with protection of human health and the environment.
V
HTTD of the soils is expected to achieve cleanup goals tor the
organic constituents in the soil. Substantial reduction of the
toxicity, volume, and mobility of the organics in the soils is
provided by this thermal treatment. The mobility and toxicity of
56
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the inorganics in the soils would be reduced by stabilization.
However, because of the addition of stabilizing material, the
volume of inorganics-impacted soil is increased. The estimated
increase in volume is 30 percent. Therefore, the 46,000 cubic
yards of soil would increase to 60,000 cubic yards after
stabilization. This additional volume of soil would be placed
on-site and is expected to increase the elevation of the final
grade by 1.5 to 2.0 feet. Approximately five gallons per minute
of wastewater from the thermal treatment unit is expected to
require treatment and discharge to a groundwater treatment
system.
Regarding the short-term effectiveness of this alternative, the
community and/or workers around and on the Peak Oil Site may
potentially be exposed to low levels of some metals or organics
due to dust emissions or volatilization during excavation of
soils. Dust or vapor suppressants would be used to reduce
emissions. This alternative also includes air quality monitoring
at the site perimeter to assess potential air impacts. Worker
protection may be required for dermal contact and inhalation of
dust.
The estimated time required to complete the remedial action
portion of this alternative is 57 weeks.
The implementation of this alternative is directly influenced by
the attainment of easements or access agreements and deed
restrictions for the site and portions of property adjacent to
the site in order for excavation and construction activities to
be completed. The substantive requirements of an air permit
would have to be met for this treatment system.
This alternative involves use of several standard construction
techniques, including construction of a slurry wall. The
availability of the thermal treatment processing systems is
limited, but at least two vendors provide this service.
The cost to implement this alternative is presented in Table 7-1.
Asv shown, the present-worth cost of this alternative is estimated
to be $24,155,000. This cost is based on excavation and
treatment of 46,000 cubic yards of soil.
7.5 Alternative No. 5: Off-Site Disposal
The off-site disposal alternative consists of excavating impacted
soil for off-site treatment at a RCRA-permitted Toxic Substance
Disposal Facility (TSDF). This alternative would contain the
same access restrictions, site preparation, and slurry wall
construction components as Alternative No. 2. Because impacted
soil and/or treated media would not remain on-site, a cap is not
57
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part of this alternative. Soil dewatering and excavation for
this alternative would be the same as described for the ex-situ
alternatives. The major components of this alternative include:
\
o - Demolition of facilities, fence, and railroad tracks which
hinder construction of slurry wall and excavation of soils;
o Installation of a slurry wall around the soils impacted
above the established cleanup concentrations;
o Installation of dewatering sumps for dewatering site soils
to the depth of excavation. Groundwater removed during
dewatering would be treated by a groundwater treatment
system;
o Excavation of site soils requiring remediation;
o Air quality monitoring at the site perimeter during .
excavation activities;
o Initial solidification of the site soils (if necessary) for
transportation purposes;
o Off-site disposal at a regulated TSDF;
o Backfill of excavation with clean fill, and grading of
filled area to drain surface water runoff to the ditch south
of Reeves Southeastern Wire and to the ditch north of the
Peak Oil Site;
o Removal of portions of the slurry wall to allow for future
drainage of site area;
o Revegetation of site with indigenous plants.
For this alternative, due to the quantity of soil (46,000 cubic
yards) to be removed from the site, preliminary waste profiling,
scheduling, and necessary contracts would be required with
permitted hazardous waste haulers and TSDFs. Excavation of the
impacted source soils would be initiated after construction of
the slurry wall and site dewatering.
LDRs require the soil to be treated before disposing into a RCRA
landfill. LDR treatment standards may require the soil be
incinerated to remove organics, and the resulting ash stabilized
for inorganics. Existing capacity limits at commercially
operated permitted incinerators would require that the excavation
and transportation of impacted soil be conducted on a schedule
compatible with incinerator capacity limits. The cost ef this
alternative is based on the incineration and stabilization of the
soil.
58
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Soils contaminated with PCBs over 50 ppm would require selective
excavation and incineration at a Toxic Substance Control Act
(TSCA)-approved and -permitted incinerator. Approximately
1,300 cubic yards of soil would require shipment to a
TSCA-approved incinerator. The remaining 44,700 cubic yards
can be transported to a RCRA-permitted incinerator.
After impacted soils are removed from the site, clean soil would
be imported to backfill the excavations. Portions of the slurry
wall would be removed to allow proper drainage of the site area.
Summary of Remedial Alternative Evaluation:
Overall protection of human health and the environment is
provided by this alternative by removing all impacted source
soils from the site. However, because this alternative involves
off-site disposal of the impacted soil, it is contrary to the
statutory preference of SARA for on-site remedies.
The long-term effectiveness of this alternative is provided by
the permanent removal of contaminants in.the soil. No on-site
residuals would remain in the source area. Off-site treatment
and disposal is a reliable and adequate method for removal of the
on-site hazard.
This alternative would comply with all chemical-, location-, and
action-specific ARARs for the Peak Oil Site. This is
accomplished by removing all source soils at the site. This
alternative would comply with all LDRs.
This alternative effectively reduces toxicity, mobility, and
volume of chemical constituents in the site soil. Assuming soils
would require incineration and stabilization in order to meet
LDRs, toxicity and volume of constituents in the soils at the
off-site facilities would be reduced as well.
Approximately 44,700 cubic yards of soil would be disposed of as
non-PCB-impacted soil at a RCRA facility, and the remaining 1,300
cubic yards of soil would be treated and disposed of at a TSCA/
RCRA-approved facility.
Regarding the short-term effectiveness of this alternative, the
transportation of impacted soil increases truck traffic in the
site area, and thereby increases potential for an accident. The
potential for exposure of persons and the environment to site
contaminants because of potential wrecks by the transportation
vehicle exists for this alternative. Additionally, potential for
exposure by workers and the community to organic vapors or
impacted dust during excavation activities exists. However,
exposure to vapors and dust would be reduced by monitoring and by
engineering controls (i.e., vapor or dust suppressants, air
monitoring, and personal protective equipment).
59
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The estimated time required to complete the remedial action
portion of this alternative is 39 weeks. However, this time for
completion assumes that there is adequate capacity at an off-site
TSDF.
The implementability of this alternative is dependent on the
acquisition of easements or purchase of property adjacent to the
site. Additionally, removal of facilities and railroad tracks on
and near the site would be necessary. However, this alternative
is technically implementable.
The cost to implement this alternative is presented in Table 7-1.
As shown, the present-worth cost of this alternative is estimated
to be $120,103,000. This cost is based on the assumption that
46,000 cubic yards of soil would require incineration and
stabilization due to LDRs.
Ash Pile
Based on RI results, the PRPs conducted a Feasibility Study (FS)
under EPA's oversight to identify and evaluate appropriate
remedial alternatives for minimizing risks to human health and
the environment which could be caused by the contaminated ash
pile at the site. EPA considered three alternatives.
7.6 Alternative No. 1: No Action
The National Contingency Plan (NCP) requires the development of a
no action alternative as a basis for comparing other
alternatives. Therefore, this alternative would mean no further
action would be taken to reduce the risks posed by the ash pile
contamination. The ash pile will remain at its current location
with no maintenance of the protective plastic liner and/or cover.
Summary of Remedial Alternative Evaluation:
Protection of human health or groundwater will not be achieved
with the no-action alternative because there will be no reduction
of inorganic chemical concentrations nor will the chemicals of
concern be immobilized.
This alternative will not comply with chemical-, location-, or
action-specific ARARs because leachable contaminants which may
contribute to noncompliance with groundwater ARARs will not be
reduced or eliminated.
Because the no-action alternative does not meet the two threshold
criteria of overall protection of human health and the *
environment or compliance with ARARs, it will not be carried
through the other seven criteria.
I
60
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There is no cost associated with the No Action alternative.
7.7 Alternative No. 2: Solidification/Stabilization and On-Site
Disposal
o Solidification/Stabilization of ash pile using suitable
solidifying/stabilizing reagents
o On-site placement of solidified/stabilized material over
northern portion of the site and temporary coverage with an
interim protective plastic cover
o Place multimedia cover over solidified mass after entire
site treatment is completed
Alternative No. 2 involves the stabilization and solidification
of the ash pile by the addition of a solidification reagent
forming a high-strength, low-permeability material with the
contaminants encapsulated within the matrix of the material.
The material will be spread out over the.northern part of the
site for approximately 1.2 acres. A protective plastic cover
will be placed on the mound until the completion of the treatment
of the entire site, at which time a multimedia cap will be placed
on the solidified ash. This alternative reduces the leaching
potential of the ash pile contaminants into the surficial
aquifer.
Summary of Remedial Alternative Evaluation:
This alternative will not result in a reduction of inorganic
chemical concentrations, but the chemicals of concern will be
immobilized thereby reducing risks to human health and the
environment.
This alternative will comply with chemical-, location-, and
action-specific ARARs.
The long-term effectiveness of this alternative is provided by
solidification/stabilization of the leachable inorganic compounds
in the ash pile. Eventually, placement of the multimedia cap
after treatment of the entire site will add to the overall
protectiveness of the remedy.
The mobility of the contaminants will be reduced by
solidification/stabilization. However, for solidification, the
volume of the ash pile may increase by up to approximately 10
percent. For the stabilization process, the volume of the ash
pile is expected to remain constant or decrease due to the
reduction of pore space in the ash caused by chemical bending.
The toxicity of the ash pile will remain unchanged, but the risk
of exposure to the environment will be greatly decreased.
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The cost of Alternative No. 2 is $726,165.
7.8 Alternative 3: Solidification/Stabilization and Off-Site
Disposal
*
o Solidification/Stabilization of ash pile using suitable
solidifying/stabilizing reagents
\
o Transportation and off-site disposal of solidified/
stabilized material
This alternative calls for the same solidification and
stabilization as in Alternative 2, but a different means of
disposal. The material would be transported to an off-site
landfill for disposal. The risk of contaminant exposure to human
health and the environment will be greatly decreased by the
removal of the material from the site.
Summary of Remedial Alternative Evaluation:
This alternative will provide overall protection of human health
and the environment by solidifying/stabilizing and removing the
entire ash pile from the site.
The long-term effectiveness of this alternative is provided by
the permanent removal of contaminants in the ash pile area of the
site. No on-site residuals will remain from the ash pile.
Solidification/stabilization and off-site disposal is a reliable
and adequate method for removal of the on-site hazard.
This alternative will comply with all chemical-, location-, and
action-specific ARARs by solidifying/stabilizing and removing the
ash pile from the site.
This alternative effectively reduces the toxicity, mobility and
volume of the chemicals of concern in the ash pile at the site.
If solidification is used, the volume may increase by up to 10
percent. The toxicity will remain unchanged, but risk of
exposure will be greatly decreased.
The cost of this alternative for nonhazardous disposal is
$1,124,550. The cost of this alternative for hazardous disposal
is $6,198,390.
8.0 Comparative Analysis of Remedial Alternatives
A detailed comparative analysis was performed on the remedial
alternatives developed for both the source material and ash pile
during the FS and the modifications submitted during the public
comment period using the nine evaluation criteria set forth in
the NCP. The advantages and disadvantages of each alternative
were compared to identify the alternative with the best balance
\
62
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among these nine criteria. A glossary of the evaluation criteria
is provided in Table 8-1. According to the NCP, the first two
criteria are labeled "Threshold Criteria", relating to statutory
requirements that each alternative must satisfy in order to be
eligible for selection.- The next five criteria are labeled
"Primary Balancing Criteria", which are technical criteria upon
which the detailed analysis is primarily based. The final two
criteria are known as 'Modifying Criteria", assessing the
public's and State agency's acceptance of the alternative. Based
on these final two criteria, EPA may modify aspects of the
specific alternative.
A summary of the relative performance of each alternative with
respect to the nine evaluation criteria is provided in the
following subsections. A comparison is made between each of the
alternatives for achievement of a specific criterion.
Soils and Sediments
8.1 Overall Protection of Human Health and the Environment
i
" The first criterion against which each 6f the remedial
alternatives is analyzed in detail is that of overall protection
of human health and the environment. CERCLA mandates that
remedial actions provide this protection. Each remedial
alternative is analyzed to determine whether it will eliminate,
reduce, or control the risks identified in the Baseline RA. The
remedial alternatives are also evaluated to determine whether
unacceptable short-term or cross-media impacts will result from
implementation. Overall protection of human health and the
environment draws on the assessments of other evaluation
criteria, especially long-term effectiveness and permanence,
short-term effectiveness, and compliance with ARARs.
Because the Baseline RA shows the risks due to exposure to site
soils are within the range considered adequately protective of
human health for current site conditions, all alternatives
evaluated in the source control FS will provide protection of
human health insofar as exposure to soils and sediments is
concerned. However, the risk to human health associated with
exposure to groundwater is unacceptable. Currently,
concentrations of chemicals above MCLs exist in the surficial
aquifer at the Peak Oil Site. Concentrations of these chemicals
in site source soils contribute to the elevated (above MCLs)
groundwater concentrations. Therefore, cleanup concentrations
which are considered protective of groundwater were established.
All of the alternatives, except the No-Action Alternative, are
protective of human health and the environment by eliminating,
reducing, or controlling risk through treatment of soil*
contaminants, engineering controls, and/or institutional
controls. Since the No-Action Alternative (Alternative No. 1)
does not eliminate, reduce or control any of the exposure
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Table 8-1
GLOSSARY OF EVALUATION CRITERIA
THRESHOLD CRITERIA:
Overall Protection of Human Health and the Environment -
addresses whether or not a remedy provides adequate protection
and describes how risks posed through each pathway are
eliminated, reduced, or controlled through treatment, engineering
controls or institutional controls.
Compliance with ARARs - addresses whether or not a remedy will
meet all of the applicable or relevant and appropriate
requirements of other federal and state environmental statutes
and/or provides grounds for invoking a waiver.
PRIMARY BALANCING CRITERIA:
Long-Term Effectiveness and Permanence - refers to the magnitude
of residual risk and the ability of a remedy to maintain reliable
protection of human health and the environment over time once
cleanup goals have been met.
Reduction of Toxicitv, Mobility, or Volume Through Treatment -
addresses the anticipated performance of the treatment
technologies that may be employed in a remedy.
Short-Term Effectiveness - refers to the speed with which the
remedy achieves protection, as well as the remedy's potential to
create adverse impacts on human health and the environment that
may result during the construction and implementation period.
Tmpl «=»m«»n'ha'h3.1itv — is the technical and administrative
feasibility of a remedy, including the availability of materials
and services needed to implement the chosen solution.
Cost - includes capital and operation and maintenance costs.
MODIFYING CRITERIA:
State Acceptance - indicates whether the State concurs with,
opposes, or has no comment on the Proposed Plan.
Community Acceptance — the Responsiveness Summary in the appendix
of the Record of Decision reviews the public comments received
from the Proposed Plan public meeting and the public comment
period.
64
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pathways, it is therefore not protective of human health or the
environment and will not be considered further in this analysis
as an option for the soil wastes.
The-most permanent protection of the environment is provided by
Alternative No. 5 because the source soil is removed, thus
removing the source of surficial aquifer degradation at the-site.
Alternatives No. 3 and No. 4 treat the source soils. This is a
permanent solution to the degradation of the surficial aquifer;
however, depending on the ability of treatment to meet cleanup
goals, some chemicals may remain on-site. Therefore, these
alternatives are considered slightly less permanent than
Alternative No. 5 at protecting the environment at the site.
Alternative No. 2 contains the impacted source soils within the
slurry wall. Because groundwater is not treated by this
alternative, chemicals would remain in the surficial aquifer
within the slurry wall. Therefore this alternative is less
protective of the environment than Alternatives No. 3, No. 4,
or*No. 5.
8.2 Compliance with Applicable or Relevant and Appropriate
Requirements (ARARs)
The second evaluation criterion in the detailed analysis of
alternatives is compliance with ARARs. Each remedial alternative
is assessed to determine whether it will attain the requirements
that are applicable, or relevant and appropriate, under the
federal and state environmental laws. Unless a waiver is
justified, the remedial alternative must be in compliance with
all chemical-specific, location-specific, or action-specific
ARARs.
Alternative No. 5 would comply with all chemical-, location-, and
action-specific ARARs for the Peak Oil Site. This is accomplished
by removing all source soils at the site. This alternative would
also comply with all land disposal restrictions.
Alternatives No. 3 and No. 4 would comply with all chemical-,
location-, and action-specific ARARs. Because soil is treated,
these alternatives would reduce or eliminate source soil
contribution to groundwater which could result in exceeding
ARARs. Also, Alternative No. 4 would meet applicable landfill
design, operation, and closure requirements. For Alternative No.
4, soil which would be backfilled into the excavation after
treatment and stabilization, would comply with land disposal
restrictions, and wastewater from the treatment operations can
meet appropriate ARARs for process wastewater discharge-; Air
emissions from the high-temperature thermal desorption unit of
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Alternative No. 4B would meet appropriate standards. For
Alternative No. 3, groundwater would be adequately treated to
meet appropriate ARARs for recharge.
Alternative No. 2 would not comply with all ARARs. The cap would
be constructed in a manner which complies with action-specific
ARARs. The cap construction and site regrading would not damage
the nearby wetlands. Therefore, location-specific ARARs would be
achieved. However, surficial groundwater contained within the
slurry wall would not be treated in this alternative, and thus
would not be in compliance with groundwater ARARs.
8.3 Long-Term Effectiveness and Permanence
The third evaluation criterion for the detailed analysis is the
long-term effectiveness and permanence of the remedial action.
The degree to which each remedial alternative provides a long-
term, effective, and permanent remedy is assessed, and the degree
of certainty that the alternative will be successful in achieving
the response objectives is evaluated. This assessment includes
factors such as an evaluation of the magnitude of the risks
remaining at the conclusion of remedial 'activities, the degree to
which treated residuals remain hazardous (considering volume,
toxicity, mobility, and propensity to bioaccumulate), the
adequacy and reliability of controls (such as slurry walls, caps,
and the integrity of off-site landfills), and the potential
exposure pathways and risks posed should the remedial action
require replacement.
Long-term effectiveness is provided by Alternative No. 5 because
source soils are completely removed. Also, the removal and
disposal techniques used for this alternative are considered
reliable and adequate as long-term remedies. Five-year reviews
would not be necessary for this alternative because all source
contamination is removed from the site.
Alternatives No. 3 and 4 have adequate long-term effectiveness,
but because stabilized soil would remain on-site after
implementation of these alternatives, continued implementation of
deed restrictions and maintenance are required. Although, in
relation to one another, Alternative No. 4 has the capacity to
achieve lower cleanup levels than Alternative No. 3, the long-
term effectiveness of these alternatives is relatively the same.
Alternative No. 2 is dependent upon control measures to be
effective. Whereas Alternatives No. 3 through No. 5 provide
treatment and a permanent reduction in contamination,
Alternative 2 relies upon a greater amount of engineering
controls, inspection, and maintenance to assure effectiveness.
Five-year site reviews are necessary for Alternative 2.
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8.4 Reduction of Toxicity, Mobility, or Volume Through
Treatment
The fourth evaluation criterion for the detailed analysis is the
reduction of toxicity, mobility, or volume through treatment or
recycling. Each alternative is evaluated against this criterion
to assess the anticipated performance of the treatment
technologies used in the alternative to achieve the reduction in
toxicity, mobility, and/or volume of the principal threats.
CERCLA requires that a preference be given to treatment
alternatives which reduce the toxicity, mobility, or volume of
hazardous constituents. As part of this analysis, the evaluation
considers the following:
1. The treatment or recycling processes proposed and the
waste materials the processes will handle;
2. The amount of hazardous substances destroyed, treated,
or recycled;
3. The degree of expected reduction in toxicity, mobility,
or volume of the waste due to"treatment or recycling
* and the specification of which reduction(s) are
occurring;
4. The degree to which treatment is irreversible;
5. The types and quantities of residuals that will remain
following treatment, considering the persistence,-'
toxicity, mobility, and propensity to bioaccumulate of
the hazardous substances which may remain in the
residuals;
6. The degree to which treatment reduces the inherent
hazards posed by the principal threats.
The maximum reduction of toxicity, mobility, and volume of
chemical constituents in the site soil is provided by Alternative
No. 5. Soils would be incinerated or otherwise treated off-site
at treatment and disposal facilities, thus reducing the'toxicity
and volume of constituents in the soils at the site.
Alternative No. 4B is expected to achieve cleanup goals for the
organic constituents in the soil. The toxicity, volume, and
mobility of the organics in the soils would be substantially
reduced. Stabilizers which would be added to the thermally
treated soils are expected to eliminate the mobility and toxicity
of the metals in the soil. However, because of the addition of
stabilizing material, the volume of remediated soil is increased.
The estimated increase in volume is approximately 30 percent.
Therefore, the 46,000 cubic yards of thermally treated soil would
increase to 60,000 cubic yards after stabilization.
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Approximately five gallons per minute of wastewater from the
thermal treatment unit is expected to require treatment.
The toxicity, mobility, and volume of site impacted soil would be
substantially reduced by Alternative No. 4A. However, a
treatability study must be conducted to determine the achievable
cleanup levels. Approximately 46,000 cubic yards of soil would
be processed by soil washing and about 7,000 cubic yards of fines
would be stabilized. The 7,000 cubic yards of fines for
stabilization would bulk about 30 percent to produce 9,000 cubic
yards of stabilized material for backfill into the excavation.
Wastewater sludge produced by the soil washing process is
included in this volume.
Alternative No. 3 substantially reduces the mobility of site
chemicals. Toxicity and volume of chemicals are also reduced. A
treatability study is required to estimate the achievable cleanup
levels.
Alternative No. 2 eliminates migration of.constituents from the
site and thus reduces the mobility of site chemicals. However,
the toxicity and volume of the impacted source soil would remain
essentially unchanged.
8.5 Short-Term Effectiveness
The fifth criterion, short-term effectiveness, addresses the
effectiveness of the alternative during construction and
operation of the remedial action. Alternatives are evaluated
with respect to their effects on human health and the
environment, including the risks to the community posed by
implementation of the action, protection of the workers during
implementation and the reliability and effectiveness of
protective measures available to the workers/ potential impacts
to the environment caused by the remedial alternative and the
effectiveness and reliability of mitigative measures which could
be employed during implementation, and the time required to
achieve the final response objectives.
Alternatives No. 2 and No. 3 result in small, if any, short-term
effects. Construction of these alternatives may result in short-
term increase in exposure potential to the community and on-site
workers. Construction of the slurry wall may cause
volatilization of organics into the air or emission of impacted
dust, thus resulting in temporary impacts to the ambient air
quality. The time to complete Alternative No. 2 is 12 weeks and
the time required for the slurry wall phase of Alternative No. 3
is 4 weeks.
»
Regarding the short-term effectiveness of Alternative No. 4, the
community and/or workers around and on the Peak Oil Site may
potentially be exposed to low levels of some metals or organics
68
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due to dust emissions or volatilization during excavation of
soils. This alternative includes air quality monitoring at the
site perimeter to assess potential air impacts. If unacceptable
concentrations are detected in air during excavation, work would
be discontinued until the concentrations subside. Worker
protection may be required for dermal contact and inhalation of
dust.
It is expected that Alternatives No. 4A and No. 4B would require
60 and 57 weeks, respectively, to implement.
Alternative No. 4B has, in addition to the short-term effects
listed above, the potential of air emissions from the thermal
treatment unit. Although monitoring would be used to protect
workers and the environment, potential of exposure is present.
Therefore, this alternative has less short-term effectiveness
than Alternative No. 4A.
In Alternative No. 5, transportation of impacted soil increases
truck traffic in the site area, and thereby increases potential
for vehicular accidents. The potential for exposure of persons
and the environment to site chemicals because of potential wrecks
by the transportation vehicle exists for this alternative.
Additionally, potential for exposure of workers and the community
to organic vapors or impacted vapor and dust during excavation
activities exists. However, exposure to vapors and dust would be
reduced by monitoring and by engineering controls (i.e., vapor,
dust suppressants, air monitoring, and personal protective
equipment). This alternative is expected to require only 39
weeks to implement.
8.6 Implementability
The sixth criterion upon which the detailed analysis of remedial
alternatives is based is implementability. This criterion
involves analysis of ease or difficulty of implementation,
considering the following factors:
1. Technical feasibility, that is, the feasibility to
reliably construct, operate, and monitor the
effectiveness of a remedial action, as well as
potential technical difficulties or unknowns associated
with construction or operation;
2. Administrative feasibility, that is, the feasibility of
obtaining permits or rights-of-way for construction or
operation, and coordinating interagency approvals or
k activities;
«>
3. Availability of services and materials for a treatment
method or technology, such as the availability of
disposal capacity, off-site treatment or storage
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capacity, availability of equipment or specialists, and
availability of special resources (e.g., catalysts,
polymers, or borrow clays).
All-alternatives reviewed are administratively and technically
implementable. The most easily implemented alternative for
remediation at the Peak Oil Site is the limited action
alternative. Implementation of deed restrictions would be
required, which is administratively feasible. The inspection of
the site fence and warning signs, as well as five-year reviews,
are easily implemented.
Common to the remainder of the alternatives are several items
which are critical to implementation. The implementability of
each of these alternatives is dependent on the acquisition of
easements or purchase of property adjacent to the site for the
construction of the slurry wall. The attainment of access.
agreements and construction of the slurry wall are both .
considered administratively and technically implementable.
Additionally, removal of facilities and railroad tracks on and
near the site would be necessary for all the remaining
alternatives.
i
Alternatives No. 2 and No. 3 require access to the adjacent areas
because of the construction of the multimedia cap within the
confines of the slurry wall. Additionally, these alternatives
require implementation of site fence, signs, and cap inspection
and maintenance programs, as well as five-year site reviews.
Alternatives No. 2 and No. 3 utilize proven and reliable
construction methods and services which are readily implemented
and available. Minimal construction is required with these
alternatives. Alternative No. 3 includes installation of an
in-situ treatment system and a treatability study.
Alternative No. 4A is the fourth most easily implemented
alternative. The availability of the soil washing system is not
considered to be a problem. The construction and operation area
of approximately 100 feet by 150 feet, which can be situated in
the northwest corner of the site. As noted in earlier sections,
a treatability study is required for this alternative.
Almost equally as implementable as the soil washing alternative
is Alternative No. 4B. The availability of the treatment system
is slightly less than the soil washing system, but it also is
generally available. The construction and operation area of 150
feet by 150 feet for this treatment system can be situated in the
northwest corner of the site. This alternative also requires a
treatability study. *
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Alternative No. 5 is counter to the statutory preference of SARA,
and is contingent upon limited TSDF capacity. However, this
alternative is technically and administratively implementable.
8.7 -Cost
The seventh criterion for detailed analysis of alternatives -is
cost. Both capital and operational and maintenance (O&M) costs
are considered. The accuracy of the cost estimates is generally
within the range of -30 percent to +50 percent. To facilitate
comparison of alternatives with expenditures occurring over
different time periods, all costs are presented in terms of
present worth. A discount rate of 10 percent has been utilized
as recommended by the Office of Management and Budget (OMB)
guidance (OMB Circular No. A-94).
In the Feasibility Study, engineering, legal, and administrative
costs were assumed to equal 15 percent of the direct capital
costs and contingency costs were assumed to equal 20 percent of
the direct capital costs for each alternative.
Costs for the five alternatives are listed below in ascending
order of magnitude.
i Alternative No. 1A: No cost
Alternative No. IB: Present-worth cost = $123,000;
Alternative No. 2: Present-worth cost = $1,683,000;
Alternative No. 3: Present-worth cost = $3,221,000;
Alternative No. 4:
- No. 4A: Present-worth cost = $13,908,000;
- No. 4B: Present-worth cost = $24,155,000;
Alternative No. 5: Present-worth cost = $120,103,000.
8.8 State Acceptance
This criterion assesses the technical and administrative issues
and concerns the state may have regarding each of the remedial
alternatives. Many of these concerns are addressed through
compliance with applicable ARARs.
The State of Florida, as represented by the Florida Department of
Environmental Regulation (FDER), has been the support agency
during the Remedial Investigation and Feasibility Study process
for the Bay Drums site. In accordance with 40 CFR 300.430, as
the support agency* FDER has provided input during this process.
Based upon comments received from FDER, it is expected that
concurrence will be forthcoming; however, a formal letter of
concurrence has not yet been received.
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8.9 Community Acceptance
This criterion assesses the issues and concerns the public may
have regarding each of the remedial alternatives. This criterion
is addressed in the Responsiveness Summary, Appendix A of this
document.
Based on comments made by citizens and government officials at
the public meeting held on August 18, 1992, and those received
during the public comment period, the Agency perceives that the
community believes that the overall selected remedy of In-Situ
Treatment for contaminated soils and sediments will effectively
protect human health and the environment.
Ash Pile
8.10 Overall Protection of Human Health *«<* the Environment
Alternative 1 will not be protective of human health nor the
environment as metals from the untreated.ash will not be
solidified/stabilized and may become available for human
exposure, or may potentially leach into the aquifer. Both
Alternatives 2 and 3 will provide protection of human health and
the environment because the metals in the ash pile will be
stabilized, and unable to leach into the surficial aquifer.
Alternative 3 is the most permanent solution because the ash pile
will be removed from the site, thus eliminating all site risks
associated with it.
8.11 Compliance with Applicable or Relevant and Appropriate
Requirements (ARARs)
Alternative 1 will not comply with chemical-, location-, and
action-specific ARARs as the contaminants in the untreated ash
pile may leach into the groundwater thus exceeding ARARs. Both
solidification/stabilization alternatives will comply with all
ARARs for the Peak Oil Site. This is accomplished by stabilizing
thte metals which will eliminate any contaminant contribution to
groundwater that could result in exceeding ARARs. The
solidification will also comply with Land Disposal Restrictions
(LDRs) for Alternative 3.
Because Alternative No. 1 does not meet the criteria for
protection of human health and the environment or compliance with
ARARs, it is not carried through the other criteria.
8.12 Long-Term Effectiveness
Long-term effectiveness will be provided by both «•
solidification/stabilization alternatives (Alternative 2 and 3)
because the metals will be stabilized during the solidification
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process. However, Alternative 3 will provide additional long-
term effectiveness due to the fact that the solidified ash pile
will be removed from the site.
8.13 Reduction of Toxicity, Mobility, or Volume
The solidification process used in both Alternative 2 and 3 -will
reduce the mobility of the chemicals of concern. However, -the
volume may increase by up to approximately 10 to 20 percent. For
the stabilization process, the volume of the pile is expected to
remain constant or may decrease due to the reduction of pore
space in the ash caused by chemical bonding. The off-site
disposal for Alternative 3 will achieve the maximum reduction of
the mobility, toxicity, and volume of the contaminants in the ash
pile because the ash pile will be removed from the site.
8.14 Short-Term Effectiveness
Alternative 2 will result in small, if any, short-term effects.
Some fugitive dust may be generated during the solidification
process. However, this may be reduced by using proper
engineering controls. Alternative 3 may also result in the
generation of fugitive dust during solidification, but
engineering controls can reduce this effect.
8.15 Zmplementability
All alternatives reviewed are administratively and technically
implementable. The most easily implemented alternative is the no
action alternative. Alternative 2 uses proven reliable
construction methods that are readily implementable and
available. The administrative feasibility of off-site disposal
in Alternative 3 may be complicated by the problems associated
with landfill acceptance of waste from a Superfund site. Also,
this alternative is counter to the statutory preference of SARA
for on-site remedies.
8.16 Cost
Alternative 1 has no costs associated with it since no further
action would be taken. Alternatives 2 and 3 were ranked based on
the total costs presented. Alternative 2 was significantly lower
in costs due to the high transportation and disposal costs
associated with Alternative 3. The costs are listed below:
Alternative No. 1: No Action = No Cost
Alternative No. 2: Solidification/On-Site Disposal= $726,165
Alternative No. 3: Solidification/Off-Site Disposal
Nonhazardous Disposal = $1,124,§50
k Hazardous Disposal = $6,198,390
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8.17 State Acceptance
The State of Florida, as represented by the Florida Department of
Environmental Regulation (FDER), has been the support agency
during the Remedial Investigation and Feasibility Study process
for the Bay Drums site. In accordance with 40 CFR 300.430, as
the support agency, FDER has provided input during this process.
Based upon comments received from FDER, it is expected that
concurrence will be forthcoming; however, a formal letter of
concurrence has not yet been received.
8.18 Community Acceptance
Based on comments made by citizens and government officials at
the public meeting held on February 24, 1992, and those received
during the public comment period, the Agency perceives that the
community believes that the selected remedy of solidification/
stabilization of the ash pile with on-site disposal will .
effectively protect human health and the environment.
The public comments that were expressed during the public meeting
and the public comment period have been addressed in the
Responsiveness Summary, Appendix A.
9.0 Selected Remedy
Based upon consideration of the requirements of CERCLA, the NCP,
the detailed analysis of the RI/FS, the risk assessment, and
public and state comments, EPA has selected Alternative No. 3 for
soils and sediments and Alternative No. 2 for the ash pile at the
Peak Oil site. At the completion of this remedy, the risk
associated with this site has been calculated at 10"4 which is
determined to be protective of human health and the environment.
The total present worth cost of the soil and sediment selected
remedy, Alternative No. 3, is estimated at $3,221,000, which when
added to the cost of the ash pile remedy of $726,165 yields a
total project cost of $3,947,165.
V
9.1 Source Control
Source control remediation will address the contaminated
soils/sediments and the ash pile at the site. Source control
shall include installation of a slurry wall around the site,
excavation, solidification/stabilization and on-site disposal of
lead-impacted soils/sediments, solidification/stabilization and
on-site disposal of the ash pile, dewatering of surficial
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aquifer, treatment of surficial groundwater1, in-situ soil
flushing/bioremediation, and capping of the site. Following
source control remediation, institutional controls will be placed
on the site.
•
9.1.1 The ma-jor components of source control to be implemented
include:
o Construction of a slurry wall around the impacted site
soils. The slurry wall will be composed of a clay material
and will be keyed into the Hawthorn Formation at an average
depth of 20 feet.
o Excavation and solidification/stabilization of lead-impacted
soil with concentrations above the remediation goal of
284 mg/kg. The solidified material will be comprised of a
pozzolan-Portland cement mixture which involves a
combination of Portland cement and fly ash or other .
pozzolans to produce a relatively high-strength low
permeability monolith. Treat ability ..studies shall be
conducted to determine whether treatment of the organic-
contaminated soils is necessary prior to solidification of
the soils contaminated with lead. This is necessary due to
the areas being contaminated with lead also being
contaminated with organic substances which may hinder the
ability to meet solidification performance standards. If
treatability studies illustrate that performance standards
cannot be met, the solidification phase of remediation will
occur after completion of the soil flushing/bioremediation
phase (treatment of organics) outlined below.
o Stabilization/Solidification of the lead-impacted soils and
ash pile.
o On-site disposal of the solidified/stabilized soil and ash.
o Installation of a groundwater recovery system which includes
extraction wells and collection header piping.
o Extraction and treatment of the groundwater (See Footnote #1
on page 74).
1 The alternatives for groundwater treatment are outlined in
the Area-Wide Hvdroloqic Remedial Investigation and Baseline
Risk Assessment report. The selected groundwater remedy
will be presented in the Peak Oil/Bay Drums Operable Unit 2
Record of Decision.
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o Installation of a bioremediation mixing system to add
necessary nutrients and dissolved oxygen (or hydrogen
peroxide) to the treated groundwater for infiltration. The
nutrients are introduced to the soils via the treated
- groundwater to propagate indigenous species or
microorganisms which are capable of digesting the organic
contaminants in the soil.
o Installation of a delivery (soil flushing) system (leach
field piping or spray irrigation) to provide infiltration of
the treated groundwater back into the soils.
o Installation of a multimedia cap after in-situ treatment is
completed. The cap will be a typical cap comprised of, but
not limited to, two feet of compacted clay, covered by a
synthetic membrane, a one-foot layer of sand, and a layer of
soils capable of supporting indigenous plants. The cap will
be in accordance with guidelines found in the EPA
v publication Final Covers on Hazardous Waste Landfills and
Surface Impoundments. (EPA 530-SW-89.--047, July 1989) .
o Groundwater monitoring to ensure that groundwater ARARs are
being met.
o Placement of institutional controls on the property such as
permanent deed restrictions or zoning controls which
prohibit any development of the site or any construction
activities that may damage the treatment system or cap.
o Five-year reviews to assess whether additional remedial
actions are necessary.
9.1.2 Performance Standards
Performance standards for the treatment of soils/sediments were
developed to protect human health, to prevent contamination of
the groundwater and to be in compliance with ARARs. Treatment
shall continue until the remaining soils/sediments are at or
below the selected remediation goals. All treatment shall comply
with ARARs. Testing methods approved by EPA shall be used to
determine whether the performance standards have been achieved.
Tables 9-1 and 9-2 list the remediation goals for chemicals of
concern in the soils and sediments, respectively.
The remediation goal for lead in the ash pile is 284 mg/kg.
The remediation goals for lead and bis(2-ethylhexyl)-phthalate
are based upon protection of groundwater, and the remediation
goal for Aroclor-1260 is based upon the EPA recommendation for
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TABLE 9-1
SOIL CLEANUP GOALS
PEAK OIL SUPERFUND SITE
TAMPA, FLORIDA
Constituent
Aroclor-1260
Bis(2-ethylhexyl)-
phthalate
Lead
Maximum
Detected
Source Soil
Concentration
(mg/kg)
110
2.3
2,950
Arithmetic
Mean
(mg/kg)
3.91
0.848
240
Risk-Based
Soil
Cleanup
Goal
(mg/kg)
25 (c)
2,035 (b)
400 (d)
Groundwater
Protection-
Based Soil
Cleanup Goal
(mg/kg)
55 (a)
0.58 (a)
284 (a)
Soil
Cleanup
Goal
(rag/kg)
25
0.58
284 (e)
-J
vj
Notest
(a) Groundwater protection-based cleanup goal calculated using federal MCL.
(b) Risk-based value for carcinogens 1 x 10"**
(c) Risk-based value determined from EPA Guidance on Remedial Actions for
Superfund Sites with PCB Contamination.
(d) The health-based cleanup goal for lead is 400 mg/kg based on the
Uptake/Biokinetic (UBK) model.
(e) A final cleanup goaliof 284 mg/kg is used for lead based on an EPA review
of the Bay Drums, Peak Oil, and Reeves Southeastern Superfund Sites.
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TABLE 9-2
SEDIMENT CLEANUP GOALS
PEAK OIL SUPERFUND SITE
TAMPA, FLORIDA
Constituent
Bis (2-ethylhexyl) -phthalate
Lead
Aroclor-1260
Maximum Detected
Source Sediment
Concentration
(mg/kg)
220
1450
37
Sediment
Cleanup Goal
(mg/kg }
0.58 (a)
284 (b)
25 (c)
Notes:
(a) Groundwater protection-based cleanup goal calculated using
the federal MCL.
(b) Risk-based value for carcinogens 1 x.10"4-
(c) Risk-based value determined from E1?A Guidance on Remedial
Actions for Superfund Sites with PCB Contamination.
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remediation goals for PCBs in soils in industrial areas. The PCB
remediation goal information is found in the EPA publication
Guidance on Remedial Action for Superfund Sites with PCB
Contamination. (EPA/540/G-90/007, August 1990).
The FS for the site identified tetrachloroethylene,
1,1,1-trichloroethane and trichloroethylene. as contaminants-of
concern with suggested remediation goals of 0.17 mg/kg,
4.60 mg/kg and 0.31 mg/kg, respectively. It was determined that
these remediation goals were extremely low for soils and
therefore would not be included in the ROD as contaminants of
concern. However, analyses will be conducted to ensure that
levels of these contaminants in the soil are such that
groundwater ARARs are being met.
The volume of soil and sediment at the site requiring cleanup is
estimated to be approximately 46,000 cubic yards. The volume of
ash requiring remediation is estimated to be approximately 6,000
cubic yards.
For soils, sediments and ash that are contaminated with lead
exceeding the remediation goal of 284 mg/kg, solidification is
required. Based in part of on suggestions found in the EPA
publication Stabilization/Solidification of CERCLA and RCRA
Wastes. (EPA/625/6-89/022, May 1989), and in consultation with
EPA and FDER solidification personnel, EPA has determined that
the performance standards listed in Table 9-3 for the solidified
material are appropriate.
9.1.3 General Component
t
The in-situ treatment alternative (Alternative No. 3) requires a
groundwater treatment system since it combines in-situ soil
treatment (soil flushing and bioremediation) with groundwater
treatment. Surficial groundwater and contaminants flushed from
soils within the slurry wall are withdrawn by a recovery system
and treated by a physical, chemical, or biological aboveground
technique, and then treated water is recharged by an infiltration
system.
Prior to recharge, a mixing system is used to add nutrients (such
as nitrogen and phosphorus) and oxygen to support microbial
activity. Hydrogen peroxide or an air mixing system may be used
to provide the needed dissolved oxygen.
If necessary, prior to recharge, a surfactant can be mixed with
the water to enhance leaching or organic compounds present in the
soil into the groundwater. A surfactant is usually added to
reduce the interfacial tension between organic constituents and
water.
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TABLE 9-3
SOLIDIFICATION PERFORMANCE STANDARDS
PEAK OIL SUPERFDND SITE
TAMPA, FLORIDA
Performance Testing
Parameter Standard Methodology-
Permeability <. IxlO'7 EPA Method 9100-
SW846
Unconfined
Compressive
Strength > 250 psi ASTM 1633-84
Leachability < 5 mg/1 Lead TCLP
Leachability <. 1x10'12 mg/1 Modified .
ANS 16.1
<
Because certain performance standards may not be determined until
the Remedial Design phase, it shall be understood that the list
of performance standards in this section is not exclusive and may
be subject to addition and/or modification by the Agency in the
RD/RA phase.
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Groundwater monitoring will be conducted and five-year reviews
will be required to assess whether additional remedial actions
are appropriate after the in-situ treatment period.
The-capital cost for this alternative is $2,793,000 and the
operation and maintenance costs for the alternative are $428,000.
The cost of treatment for the ash pile is $726,165. The total
present worth cost of the alternative is $3,947,165.
10'. 0 Statutory Determinations
Under its legal authority, EPA's primary responsibility at
Superfund sites is to undertake remedial actions that achieve
adequate protection of human health and the environment. In
addition, Section 121 of CERCLA establishes several other
statutory requirements and preferences. These specify that, when
complete, the selected remedial action for this site must comply
with applicable or relevant and appropriate environmental
standards established under federal and state environmental laws
unless a statutory waiver is justified. .The selected remedy must
also be cost effective and utilize permanent solutions and
alternative treatment technologies or resource recovery
technologies to the maximum extent practicable. Finally, the
statute includes preference for remedies that employ treatment
technologies that permanently and significantly reduce the
toxicity, mobility or volume of hazardous wastes as their
principle element. The following sections discuss how the
selected remedy for this site meets these statutory requirements.
10.1 Protective of Human Health and the Environment
The selected remedy protects human health and the environment by
reducing the organic and inorganic chemical concentrations in the
source soils by both in-situ treatment and solidification, and in
the ash pile by solidification/stabilization. Protection of
groundwater is provided by treatment of source soils,
construction of a slurry wall, removal and treatment of the
surficial groundwater, and placement of a multimedia cap after
completion of the in-situ treatment. Also, risks associated with
exposure to the ash pile will be reduced.
10.2 Compliance with Applicable or Relevant and Appropriate
Recruirements (ARARs)
The selected remedy of installation of a slurry wall around the
site, excavation, solidification/stabilization and on-site
disposal of lead-impacted soils/sediments and ash, dewatering of
surficial aquifer, treatment of surficial groundwater, in-situ
soil flushing/ bioremediation, and capping of the site
comply with all applicable or relevant and appropriate
requirements (ARARs). The ARARs are presented below:
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Chemical-Specific ARARs
o Safe Drinking Water Act, 40 CFR 141.11-141.16, 141.50-
141.51. Relevant and appropriate in development of soil
- action levels for Aroclor-1260, Bis(2-ethylhexyl)-phthalate
and lead which are protective of site groundwater.
o Florida Drinking Water Standards, FAC 17-550. Maximum
contaminant levels for Aroclor-1260, Bis(2-ethylhexyl)-
phthalate and lead are relevant and appropriate for soil
action levels protective of site groundwater.
o Florida Groundwater Classes, Standards and Exemptions,
FAC 17-520. Relevant and appropriate in the development of
cleanup levels which are protective of site groundwater.
o Polychlorinated Biphenyls (PCBs) Spill Cleanup Policy, 40
CFR Part 761. Relevant and appropriate in the development
of cleanup levels for PCB-contaminated soils.
o EPA Guidance on Remedial Actions for Superfund Sites With
PCB Contamination, {EPA/540/G-90/007, August 1990). To be
considered in the development of cleanup levels for
PCB-contaminated soils.
o Clean Air Act, 40 CFR 50. Provides National Ambient Air
Quality Standards which are relevant and appropriate to lead
and particulate emissions resulting from remedial activities
conducted at the site.
o Florida Ambient Air Quality Standards, FAC 17-2.3. Relevant
«"fl appropriate to remedial activities conducted at the site
which may generate lead and particulate emissions.
o RCRA Toxicity Characteristics Rule, 55 FR 11798. Relevant
and appropriate in providing performance standards for lead
for TCLP testing of stabilized material.
Location-Specific ARARs
o Endangered Species Act, 50 CFR Part 402. Applicable to
remedial activities conducted at a site located in the area
of a critical habitat for endangered or threatened species.
o k Florida Rules on Hazardous Waste Warning Signs, FAC 17-736.
Identifies requirements applicable to signs around perimeter
and at entrances of site.
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Action-Specific ARARs
o Florida Air Pollution Rules, FAC 17-2.1. Applicable to
remedial activities conducted at the site which may generate
- air emissions.
10.3 Cost Effectiveness
EPA believes that the selected remedy will reduce the risk to
human health and the environment from the soils, sediments and
ash at a cost of $3,947,165. Of the four source alternatives
(3, 4A, 4B, and 5) and the two ash pile alternatives (2 and 3)
that provide high levels of long term protectiveness, Alternative
No. 3 for the soils and sediments and Alternative No. 2 for the
ash pile are the most cost effective. Alternatives No. 4A and 4B
provide approximately the same amount of long term protective-
ness, but are much more costly than Alternative No. 3. And
Alternative No. 5, although it removes all contaminated material
from the site and provides a 100% degree of reduction of risk to
human health and the environment at the site, it is significantly
higher than the other three source alternatives. For the ash
pile, Alternative No. 3 also removes all treated material from
the site and provides a 100% degree of reduction of risk to human
health and the environment at the site. However, the cost was
significantly higher than Alternative No. 2.
10.4 Utilization of Permanent Solutions to the Maximum Extent
Practicable
EPA has determined that the selected remedy represents the
maximum extent to which permanent solutions and treatment
technologies can be utilized in a cost-effective manner for the
source control operable unit at the Peak Oil Site. Of those
alternatives that are protective of human health and the
environment and comply with ARARs, EPA has determined that this
selected remedy provides the best balance of trade-offs in terms
of long-term effectiveness and permanence, reduction in toxicity,
mobility or volume through treatment, short-term effectiveness,
implementability, and cost, while also considering the statutory
preference for treatment as a principle element and considering
state arid community acceptance.
The selected remedy will effectively reduce or immobilize the
contaminants in the soils, sediments and ash and will prevent any
further direct risk to human health or threat to the groundwater.
10.5 Preference for Treatment as a Principal Element
Both organic and inorganic constituents were identified* at the
Peak Oil Site. The selected remedy will achieve substantial risk
reduction by permanently treating and containing the
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contamination. This alternative would be protective of human
health and the environment, is cost-effective, and will meet all
Federal and State requirements.
The remedy selected in this ROD provides the best balance of the
evaluation of the nine criteria EPA applies to every alternative.
It.would take approximately 5 years to reach protective cleanup
levels for the site. However, site contaminants would be
contained within the site area during the entire time by the
slurry wall which will be built around the site. This cleanup
method will also provide long-term protection to groundwater.
11.0 DOCUMENTATION OF SIGNIFICANT CHANGES
The Proposed Plan for Operable Unit 1 of the Peak Oil Site which
was released for public comment in August 1992 identified
Alternative 3 as the preferred alternative for soil and sediment
remediation. EPA reviewed all written and verbal comments
submitted during the public comment period from August 13, 1992
through September 13, 1992. Comments received during the comment
period expressed concern that the Proposed Plan did not address
the appropriate treatment and disposal of the ash pile located at
the Peak Oil site. EPA evaluated the comments and determined
that the ash pile should be addressed as part of the Operable
Unit One source control Record of Decision.
The PRPs conducted a focused RI/FS on the ash pile in November
1992. A second Proposed Plan which addressed the preferred
alternative for remediation of the ash pile was issued to the
public in February 1993. A second public meeting was conducted
on February 24, 1993 to address the preferred alternatives for
remediation of the groundwater and the preferred alternative for
remediation of the Peak Oil ash pile. The selected remedy for
the ash pile is included in this Record of Decision.
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